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Title: Saguaro National Monument, Arizona

Author: Napier Shelton
Natt N. Dodge

Release date: July 9, 2016 [eBook #52532]
Most recently updated: October 23, 2024

Language: English

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*** START OF THE PROJECT GUTENBERG EBOOK SAGUARO
NATIONAL MONUMENT, ARIZONA ***

saguaro
national
monument
ARIZONA
Napier Shelton
based on an earlier work by Natt Dodge

NATURAL HISTORY SERIES

1972
National Park Service
U.S. DEPARTMENT of the INTERIOR

ii
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C. 20402—Price $1.25
Stock Number 2405-0292

iii

preface
This book is a simple account of the natural history of Saguaro National
Monument. It is intended to help you understand the relationships between
land, climate, plants, wild animals, and man in the environment of a hot
desert. While it includes brief profiles of many representative species, it is
not intended to serve as a guide to the monument. It does indicate where the
several distinctive natural communities exist, and when and where to look
for certain plants and animals. For identification purposes, you will need
field guides.

The present edition is my revision of the 1957 book by Natt Dodge, then
naturalist for the Southwest Region of the National Park Service. The first
five and the last two chapters are essentially new; the central chapters on
plants and animals remain largely as written in the first edition.

The authors wish to thank former and present members of the monument
staff for their help and companionship, in both field and office. We are
particularly grateful to Chief Naturalist Harold T. Coss, Jr., who devoted
much time and effort to obtaining many of the photographs and, with Park
Biologist Warren F. Steenbergh, gave the manuscript a thorough scrutiny.
The cooperation and hospitality of Superintendent Harold R. Jones have
created the best possible climate for work on the revised edition. National
Park Service geologist Robert H. Rose contributed in very great measure to
the geological content. Finally, our thanks go to the many students of desert
life on whose knowledge this book has been built, and to monument visitors
who ask questions—for their concern gives hope for better relations between
man and nature.

—N.S.

v

contents
The Desert Scene, 1
The Sonoran Desert and the Monument, 3
Climate: The Vital Factor, 9
Rocks: Foundation and Soilmakers, 13
Plant and Animal Zones, 19
Desert Plants, 23
Succulents, 25
The Saguaro—Monarch of the Monument, 27
Other Common Cactuses, 33
Non-Succulents, 36
Perennials, 36
Ephemerals, 42
Major Plant Communities of Saguaro, 49
Plants of the Hills and Mountains, 55
Oak-Pine Woodland, 55
Ponderosa Pine Forest, 58
Animals and How They Survive, 61
Invertebrates, 62
Amphibians, 64
Reptiles, 64
Birds, 66
Mammals, 72
The Rhythms of Nature, 79
The Impact of Man, 83
Appendix, 87
Suggested Reading, 87
Common and Scientific Names of Plants, 89
Reptiles and Amphibians of the monument, 92

Birds of the monument, 94
Mammals of the monument, 97

vi

Brittlebush display along Cactus Forest Drive.

1

the desert scene
Scattered through the wide, lonely Sonoran Desert, isolated mountain ranges
raise jagged blue silhouettes against the sky. The high ones wear a crown of
dark pines and a speckled mantle of oaks. Lapping against their feet is the
desert sea, studded with the green masts of giant saguaro cactuses rising
above a motley crew of tough, strange, often handsome subordinates.

On either side of the Santa Cruz Valley in southeastern Arizona, Saguaro
National Monument embraces two of these ranges, with the desert lands at
their feet. Although it was established primarily to preserve impressive
stands of saguaros, it gains wholeness by including the mountains that shed
the rocky soil on which the saguaros grow. The monument is in two sections,
some 30 miles apart. The Rincon Mountain Section, east of Tucson, includes
in its 99 square miles a spectrum of plantlife ranging from saguaro
communities at the low elevations to a wet fir forest on the north slope of
8,666-foot Mica Mountain. The 24-square-mile Tucson Mountain Section,
about 12 miles west of the city, has a denser stand of saguaros, on the lower
slopes of a wild jumble of volcanic mountains dominated by 4,687-foot
Wasson Peak.

Within the cactus forests and upon the mountain slopes, life in myriad forms
goes on in a delicate and continuous adjustment to changing environments.
Over millennia, mountains rise and crumble, species evolve and fade from
the scene. Over days and weeks and years, populations of plants and animals
rise and fall, in response to thousands of interactions which we are only
beginning to understand. In the following pages, we will meet the main
characters in this natural drama (including some of the most improbable in
all of nature); we will investigate the environmental stage upon which they

perform; and we will try to understand something of the play itself,
including our own role in it.

2

The Saguaro Forest in the Tucson Mountain Section.

3

the sonoran desert
and the monument
Saguaro National Monument is at the northeastern edge of the Sonoran
Desert. Named for the state of Sonora, Mexico, in which the greater part of it
lies, this, one of four major deserts in North America, is distinguished by
differences in climate and vegetation. The Great Basin Desert, mainly in
Nevada and Utah between the Rockies and the Sierra Nevada, has cold
winters, sparse precipitation distributed fairly evenly throughout the year,
and rather simple vegetation dominated by the low shrubs, sagebrush and
saltbrush. Immediately to the south, in southern Nevada and southeastern
California, is the Mohave Desert, with cool winters during which most of the
year’s precipitation comes, and with plant cover consisting mostly of shrubs
such as creosotebush. At higher elevations grows the Joshua-tree, a giant
yucca. The Chihuahuan Desert, with cool winters and summer rainfall,
covers the broad plateau of north-central Mexico, extending into southern
New Mexico and west Texas. Its vegetation consists mostly of small
cactuses, spiny shrubs, and succulent-leaved plants such as yuccas.

Lying between the Mohave and Chihuahuan deserts, the Sonoran Desert has
both winter and summer rainfall, with spring and autumn droughts. Its mild
winters and bi-seasonal rainfall encourage a vegetation far surpassing in
lushness and variety that of the other deserts. From west to east, the land
rises and precipitation increases. Yuma, in southwestern Arizona, lying at
141 feet above sea level, gets about 3 inches a year. Tucson, in southeastern
Arizona, is at 2,400 feet elevation and averages 11 inches a year. In the
western part, where plains are extensive and mountain ranges low and far
apart, a very few small-leaved species such as creosotebush dominate.
Toward the east, mountain ranges become more numerous, shedding

material on which more kinds of plants, particularly paloverde, mesquite,
and cactuses, assume leading roles in the vegetative cover. Both sections of
the monument lie within the eastern, wetter, more diversified part of the
Sonoran Desert known as the Arizona Upland. Organ Pipe Cactus National
Monument, to the southwest, is in an area transitional between the Arizona
upland and Colorado River lowland phases of the Sonoran Desert.

4

DESERT AREAS OF NORTH AMERICA

But even between the two sections of Saguaro National Monument 5
there are differences. There is the obvious fact that the Tucson
Mountains are much lower and smaller in mass than the Rincons. And there
is the not-so-obvious fact that the Tucson Mountain Section extends to lower
elevations (2,200 as opposed to 2,700 feet). These conditions are reflected in
the somewhat warmer environment of the western section. This helps to
explain why certain Sonoran Desert plants and animals here reach their
northeastern limits; among them are ironwood, desert iguana, desert horned
lizard, western shovel-nosed snake, sidewinder, desert kangaroo rat, and the
Le Conte thrasher. The Rincon Mountain Section, by virtue of its higher
elevations, has plants and animals—such as ponderosa pine, Steller’s jay,
and whitetail deer—not found in the western section.

On the geologic time scale the Sonoran Desert, like all the earth’s present
deserts, is a recent development. Some 50 million years ago tropical forests
grew here, as they did over most of southern North America. As the
Southwest gradually became drier, new species adapted to the new
conditions evolved; and the general type of vegetation changed—with some
retrogression during wetter periods—from forest to savanna (grasslands with
scattered trees) to arid subtropical scrub (such as is now found in southern
Sonora State), and finally to the plant communities of today’s Sonoran
Desert. The last stage has occurred only during the past few million years.

The assemblage of species from which most of our present desert and lower
mountain plants were derived is known as the Madro-Tertiary Flora, to
denote its center (Sierra Madre in Mexico) and time (Tertiary period—one
million to 65 million years ago) of early development. Reflecting these
origins, a majority of the species growing below 6,000 feet elevation in the
monument today are basically Mexican or Central or South American in
their distribution.

On the higher mountains of the Sonoran Desert, however, exist species with
an entirely different ancestry. Most of the plants of the pine and fir forests of
these high places, like the plants of the Great Basin Desert, derive from the
Arcto-Tertiary Flora, which dominated the northern part of our continent

during Tertiary times. As climate changes, one or the other of these great
plant assemblages will benefit at the expense of the other. If cooler, wetter
periods return, as they did during the Pleistocene epoch, ponderosa pines,
now found above 6,000 feet, may again grow nearly as low down as today’s
cactus forests. But if the present long-term drying trend continues, the
northern plants will eventually be squeezed off their mountaintops.

Animals, to some extent, reflect the same dichotomy of origins we have seen
in the plants. Thus, on the mountaintops supporting pine and fir forests, 6
a northern contingent of animals predominates, while on the lower
slopes and desert the fauna has a Mexican character. The canyons and oak-
pine forests of middle elevations in southeastern Arizona are particularly
exciting, because in these biological islands, isolated by surrounding desert,
live many “Mexican” species of animals found nowhere else in the United
States. Naturally, mountain ranges nearest the border—such as the
Huachucas and Chiricahuas—have the greatest numbers of Mexican
specialties; but the Rincons have their share too.

The wonderful diversity of plant and animal life in Saguaro National
Monument depends on a diversity of habitats. These in turn owe their
existence to a widely varying triumvirate of environmental factors—climate,
soil, and topography. To understand the biological interplay that goes on
here, we first must know something of the environmental conditions that
circumscribe it.

Plant communities on Mica Mountain.

Geological Time Table 7

Era Period Epoch Years before Major geological
present time events
Cenozoic Quaternary Recent 10,000 Cascade Range and
Sierra Nevada
uplifted
Pleistocene
1,000,000
Tertiary Pliocene
12,000,000
Miocene

26,000,000
Oligocene
38,000,000
Eocene
54,000,000 Rocky Mountains
formed
Paleocene
65,000,000
Mesozoic Cretaceous
136,000,000
Jurassic
195,000,000
Triassic
250,000,000 Appalachian
folding
Paleozoic Permian
280,000,000
Pennsylvanian
320,000,000
Mississippian
345,000,000
Devonian
395,000,000
Silurian
440,000,000
Ordovician
500,000,000
Cambrian
570,000,000
Precambrian
8

Summer thunderstorm in the Rincon Mountain Section. The Catalina
Mountains rise in the background.

9

climate:
the vital factor
Climate is the chief arbiter of life on earth. Each plant and animal, including
man, has tolerance limits for heat and water below or above which it dies.
The Sonoran desert, with its low and uncertain rainfall and high summer
temperatures, thus presents one of earth’s most taxing environments. For
most desert plants and animals, the main problem presented by this climatic
combination is a scarcity of water. Why, we might ask, is this part of the
globe so dry?

Essentially, the dryness of the Sonoran and other southwestern deserts
results from their geographic situation. First, these lands lie east of a
persistent high-pressure cell over the eastern Pacific—part of a belt of high-
pressure cells which encircles the earth at this latitude. High-pressure
systems in the Northern Hemisphere have descending, warming, dry air in
their middles and along their eastern sides. The air that flows eastward from
the “East Pacific high” thus contains little moisture, and dictates desert
conditions over much of the Southwest. Furthermore, the mountains that
more or less ring these deserts intercept much of the meager incoming
moisture, by forcing the air to rise and cool so that its moisture condenses
and falls to the ground.

But during two periods of the year, the desert does receive rain. In winter,
the East Pacific high shifts southward with the sun, reducing its effects on
the Southwest. Now the low pressure storm systems, which at this season
move eastward across the continent, can sometimes dip far enough south to
bring rain to the Sonoran Desert. These rains are usually gentle, and cover
large areas. Their clouds may cover the sky for several days at a time.

By April, the East Pacific high has returned far enough northward to resume
its control of southwestern weather. Now the fore-summer drought sets in,
intensified by gradually rising temperatures. Day after day the sun climbs
higher in the sky, baking the earth and testing the endurance of desert life.
Then, sometime in late June or early July, clouds begin forming in the
afternoons over the mountains; finally, one day they build up to great
thunderheads. The drought ends suddenly as rain pours down and lightning
cracks the sky. Down the canyons and along the desert washes rages the
water, brown with soil. In a short time, the storm is over, and the water 10
disappears into the ground. Just 1 mile away, rain may not have fallen.

These intense, local summer rains, so different from the winter ones, have a
different origin as well. They are spawned by the Atlantic’s Bermuda high,
which has shifted northwestward and sent moist air from the Atlantic and
Gulf of Mexico flowing off its western edge toward the deserts. This air rises
quickly when it strikes hot, high mountains such as the Rincons, and its
moisture condenses to fall as rain.

Some time in September the rains of summer stop, as the Bermuda High
moves south again, removing its influence and returning the East Pacific
high to a position of dominance. The sun and wind again wring moisture
from the soil, but with diminishing effect. The thermometer no longer
reaches the 100’s as it did in June, July, and August. In November or
December, the winter rains begin. Water stays longer in the soil, because
temperatures now range between 30° and 80°. Life in the desert begins a
new cycle. This rainy period usually lasts into March.

On the mountain slopes, of course, the same seasonal patterns of heat and
precipitation occur, but they are tempered or enhanced by elevation. With
increasing elevation, temperatures decline and precipitation increases. When
July temperatures at headquarters are averaging in the nineties, they will be
in the sixties on top of the Rincons. In the cactus forest at the foot of Tanque
Verde Ridge only about 10 to 12 inches of rain fall in a year, while Manning
Camp, at 8,000 feet, gets about 18 to 25 inches. These up-slope gradients of
temperature and precipitation, as we shall see, have pronounced effects on
plant and animal life.

11

Gila monster.

12

Banded augen gneiss on Cactus Forest Drive. Javelinas formerly took
refuge from the sun in the dens under these overhanging rocks.

13

rocks:
foundation and soilmakers
Soils are derived from the fragmentation and decomposition of rocks.
Combinations of soils and climate, varying from place to place, create an
almost infinite number of environments with differences so subtle and small
as to make it appropriate to refer to them as microenvironments. Though
these differences be minor, they are often sufficient to create niches each of
which becomes a habitat for a particular group of plants and animals. Thus it
is that the saguaros and other desert vegetation in Saguaro National
Monument and vicinity are found in particular environmental or ecological
niches where just the right combinations of soils, moisture, sunlight,
temperature and other factors are present.

Since the rocks provide the foundation and the source of soils that support
the plant and animal life, it is helpful to understand something about the
origin and evolution of the rocks and the landscape of which they are a part.
Clues to this story are to be found in the composition of the rocks and their
relationships to one another.

Rocks of the three major classes—igneous, metamorphic, and sedimentary—
are found within the monument. The igneous rocks include granites and
various kinds of lava flows, together with some intrusive dikes and veins.
The metamorphic rocks are represented by gneiss and schist. Lastly,
sedimentary rocks occur as limestone, sandstone, and alluvial fill material.
Each of these great classes of rocks was formed in a different manner, and
these differences reveal the nature of the events which are a part of the
geologic history of the monument and surrounding area.

Catalina Gneiss (pronounced NICE) is the predominant rock that visitors see
in the Rincon Mountains and the Tanque Verde Ridge; exposures of granite
and schist are also found. Gneiss is a coarse-grained metamorphic rock
resembling granite, having a banded appearance, and consisting of
alternating layers of different minerals such as feldspar, quartz, mica, and
hornblende. The banding and texture reveal that the gneiss, now exposed by
uplift and erosion, was formed from parent rocks deep below the earth’s
surface during the Precambrian Era more than a half billion years ago. There
the parent rocks, subjected to pressure and heat, melted, flowed, and
crystallized, before resolidification.

Though the gneiss of the Rincon Mountains is ancient, the uplift that 14
raised it to its present height is thought to have occurred rather recently
(within the past 24 million years), during the period when most of the
Sonoran Desert ranges apparently were formed. In age, these mountains thus
would fall somewhere between the older Rockies and the younger Sierra
Nevada.

The schist, which underlies much of the Cactus Forest, where it is exposed
along washes, was probably formed during the Cretaceous period more than
65 million years ago. Like the gneiss, the schist is a metamorphic rock,
having been formed by the transformation of parent rocks at depth under
great pressure and heat. Due mainly to differences in the composition of the
parent rock, together with its mica content, the rock that resulted was platy
and cleavable (accounting for its classification as schist).

Granite, which forms Wasson and Amole peaks in the Tucson Mountain
Section, is an igneous rock that (like the metamorphic gneiss and schist)
originated at depths below the earth’s surface. The granite was formed by the
solidification of molten rock material that moved upward en masse from
greater depths, rather than by the alteration of ancestral rocks. Erosion of the
uplifted land mass has not only stripped away the overburden but has
developed valleys deeply incised into the granite itself.

Volcanic rocks in the form of rhyolite, andesite, and basalt flows also are
exposed, chiefly in the Tucson Mountain section of the monument. These are
all extrusive igneous rocks composed of magma that solidified after reaching
the earth’s surface through vents or fissures. There are differences in the lava

flows, reflecting differences in composition, temperature, and other
conditions of the magma from which they were formed. The rhyolite is
lighter in color than andesite, and it is somewhat richer in feldspar. Basalt,
on the other hand, is dark, is deficient in feldspar and quartz, and contains
relatively large amounts of the darker minerals such as hornblende,
pyroxene, and olivene. Lava flows of the rhyolite and andesite variety occur
in the Cactus Forest locality of the Rincon Mountain Section. Cat Mountain
Rhyolite is the name given to a rhyolite flow of Tertiary age that forms the
topmost layer in much of the Tucson Mountain Section. A small exposure of
basalt is also found here.

Limestone, sandstone, and shale formations are also exposed at various
places within the monument. They are reliable indicators of seas that
covered the area during one or more times of the geologic past. Comparisons
with the limestone formations farther to the south in the Colossal Cave
region indicate that the limestone in the monument was formed as far back
as late in the Paleozoic Era (345 million years or more ago). This age is
suggested by types of fossils, including fragments of crablike trilobites 15
and crinoid (sea lily) stems, found in limestones of the same age near
Colossal Cave.

The Recreation Redbeds of the Tucson Mountain Section is one of the
important sandstone members exposed in the monument. Geologists believe
that its deposition occurred early in the Cretaceous Period more than 65
million years ago. Above the Recreation Redbeds lies a formation consisting
mainly of limestone and commonly known as the Tucson Mountain
“Chaos”—an appropriate name, in view of the geologists’ meager
knowledge of it. Within the Chaos formation, believed to be lower to Middle
Tertiary in age, are limestone blocks of greater age than the rocks within
which they are entombed. No generally accepted explanations have been
advanced as to how these relationships developed.

The processes that destroy mountains continue concurrently with those that
build them. Temperature changes, weathering, and downslope creep under
the influence of gravity are among the agents which destroy the rocks and
eventually convert them into soil. Though these processes work rapidly from
a geological standpoint, in terms of the average human life span, they
progress at an imperceptible rate. Violent thunderstorms and cloudbursts,

however, cause a massive, often spectacular movement of boulders, gravel,
sand, and silt by torrential streams.

In desert regions, most of the runoff from storms sinks into the slopes,
dropping its burden along the way. Big rocks are dropped early as the
carrying power of the water diminishes with the speed of flow; smaller
fragments travel farther. The finest material is carried far out into the basins
between mountain ranges, gradually filling them. (The alluvial material in
the Tucson Basin is estimated to be 2,000 to 5,000 feet thick.) Thus desert
mountains tend to bury themselves in their own debris.

Alluvial fans (fan-shaped deposits built by rivers flowing from mountains
into lowlands) form at the mouths of canyons. Sometimes the alluvial fans of
adjacent canyons coalesce, forming the long, sweeping slope known as a
bajada (pronounced ba-HA-da). In other places the eroded bedrock extends
outward from the bases of desert mountains, forming “pediments,” which are
usually covered by a veneer of alluvial material. Pediments of this kind
stretch from the lower slopes of the Rincon Mountains. In the Tucson
Mountains the alluvial material deepens rapidly toward the Avra Valley
because the bedrock at the base of the mountain dips steeply downward.

Serious gaps remain in the story of the origin and evolution of the landscape
in Saguaro National Monument. Moreover, it is difficult to establish the
exact sequence in which the various events occurred. The composition,
texture, and relationships of the rocks, however, do reveal much about the
nature of the events and the processes that were involved.

16

During summer, mule deer and javelina frequent King Canyon, which
has the only known permanent spring in the Tucson Mountains. The
predominant rock in this major canyon northeast of the Arizona-Sonora
Desert Museum is called Amole Arkose; it is of sedimentary origin and
was deposited during the Cretaceous period.

17

GEOLOGICAL CROSS-SECTION OF SANTA CRUZ VALLEY

Faults are hypothetical

Showing:

Valley Fill
Wasson Peak
Granite
Folded and tilted Sedimentary and Volcanic Rock
Santa Cruz River
Flood Plain
Valley Fill
Tucson
Pantano Wash
Pediment
Tanque Verde Ridge
Mica Mountain
Gneiss

The presence of the limestones and sandstones indicates that that area was
submerged below the water of ancient seas one or more times in the geologic
past. The gneiss, schist, and granite bespeak deep-seated metamorphism and
magmatic intrusion, which gave these rocks the form, composition, and
texture they possess today. The lava flows are indicative of volcanic activity
that was a part of the extensive volcanism that occurred in this part of
southern Arizona. And, finally, the great alluvial fans and bajadas suggest
that these mountain ranges could bury themselves in their own products of

erosion unless the mountain-building processes in future eons continue at a
faster pace than the wearing-down processes. This evidence enables us to
perceive today’s landscape as but a transitional phase in the drama of change
that will continue for milleniums.

18

Chiminea Creek, originating in the higher elevations of the Rincon
Mountains, forms a ribbonlike oasis of hydrophytic plants, including
large trees such as sycamore, walnut, and cottonwood.

19

plant and animal zones
Mountains are biologically exciting because their elevation produces, in a
short vertical distance, the same climatic changes that occur over long
latitudinal distances. In Arizona, average temperatures drop about 4° with
each 1,000-foot rise in elevation, and precipitation increases about 4 to 5
inches. At sea level, you would have to travel about 900 miles north to
experience the climatic change found in going from the lowest part of the
monument (2,200 feet) to the top of Mica Mountain (8,600 feet). Plant-and-
animal communities change along these climatic gradients.

In southern Arizona, the sequence of vegetation types begins with desert
scrub at the lowest elevations, and ranges through desert grassland, oak
woodland and chaparral, oak-pine woodland, ponderosa pine forest, and
Douglas-fir forest, to Engelmann spruce forest on top of the highest
mountains. In the national monument, we have all these types except the last
—although desert grassland is poorly represented here because the steep
slopes squeeze it into a narrow altitudinal band; and Douglas-fir forest is
restricted to small areas in canyons and on north-facing slopes at high
elevations. A few drainageways (notably Chiminea Canyon, on the south
side of the monument) support patches of deciduous trees classified as
riparian woodland.

These vegetation zones should not be visualized as nice neat bands on the
mountainsides, however, for roughness of topography and differing
tolerances of plant species usually lead to gradual changes from one zone to
the next. Because of the greater exposure to drying heat and sunlight, each
belt occupies a higher range of elevation on south-facing slopes than on
north-facing ones. And along draws, where conditions are wetter and cooler

than on ridges at the same elevations, the vegetation zones finger down to
lower elevations; on ridges the opposite is true.

Animals are less restricted than plants to particular vegetation belts, but they,
too, show a zonation with altitude. You must look, for instance, in the
paloverde-saguaro community (part of the desert scrub type) for kangaroo
rats and cactus wrens; in the oak-pine woodland for Mexican jays; and in the
ponderosa pine forest for whitetail deer and tassel-eared squirrels.

In the Tucson Mountains, only the desert scrub type is well 20
represented, although the highest ridges support a suggestion of desert
grassland. A small patch of shrub live oaks, relicts of a wetter period,
huddles on the north side of Wasson Peak. Zonation is poorly developed here
because the mountains are low and small in mass. (Studies have shown that
mountains of smaller mass tend to have warmer and drier climates than
bulkier mountains of the same height.)

Major Vegetation Types in Saguaro National Monument

Vegetation type Average Elevations Annual Life zone
July temp. (feet) rainfall
(inches)
Prominent species

Southwestern Desert 94 2,200 to 7 to 13 Lower Sonoran
Scrub 4,000
Paloverde
Saguaro
Pricklypear
Cholla
Catclaw
Ocotillo
Creosotebush
Mesquite
[1]
Ironwood

Grassland Transition 85 3,500 to 10 to 15 Upper Sonoran
4,500
Mesquite
Beargrass
Gramagrasses
Amole
Sotol

Oak-pine-juniper 74 4,500 to 12 to 22 Upper Sonoran
Woodland and 7,000
Chaparral
Emory Oak
Mexican Blue
Oak
Shrub Live Oak
Pinyon Pine
Mountain-
mahogany
Manzanita
Skunkbush

Coniferous Forest 68 above 18 to 30 Transition and
6,000 start of Canadian
Ponderosa Pine
Gambel Oak
Buckbrush
Mountain Muhly
Douglas-fir
White Fir
Aspen
Snowberry

Mexican White
Pine

[1]
TUCSON MOUNTAIN SECTION
21
Biologists have developed several systems for classifying assemblages
of plants and animals over broad regions, and one of the most widely known
is that of C. Hart Merriam. Around the turn of the century, he conceived a
system of “life zones,” named for the parts of the continent where they are
best developed: Tropical, Lower Sonoran, Upper Sonoran, Transition,
Canadian, Hudsonian, and Arctic. In Saguaro National Monument, the
Lower Sonoran Zone corresponds to the desert scrub type; the Upper
Sonoran includes desert grassland transition, oak woodland, and oak-pine
woodland; the Transition Zone is equivalent to the ponderosa pine forest;
and the poorly represented Canadian Zone has Douglas-fir and white fir.
Because Merriam’s system is so widely used, his terms are included in the
tabulation on page 20, which summarizes the main characteristics of plant
zones in the monument.

The best way to appreciate the biotic changes that occur with elevation is to
walk or ride a horse to the top of the Rincons. But if your time or energy is
limited you can get a quick view of these sequences by driving up nearby
Mount Lemmon, in the Santa Catalina Mountains.

22

Saguaro Forest landscape from the scenic drive.

23

desert plants
When you look out over the cactus forest, in either part of Saguaro National
Monument, you may think there’s a sameness to it in all directions—
saguaros standing amid scattered shrubs. But look harder, or walk about, and
you will discover variations in the scene. First, there is a gradual change in
the vegetation from the mountain foot down the bajada or pediment to the
valley floor, as saguaros and paloverdes (green) become sparser and
creosotebushes (smaller and brownish) take over. (The monument itself does
not extend far enough from the mountain bases to include extensive
creosotebush communities, but these cover large areas in the lowest parts of
the valleys.) Then there is the luxuriant growth along washes, where
mesquites and paloverdes grow to tree size and there are more kinds of
plants. And if you are observant you may notice slight variations with each
change in slope on the rolling hills—for example, more grass growing on
their north sides. On another scale, you can see separate little communities
of plants in special situations, as under shrubs or on rocks.

These patterns are due to variations in the environment. For the desert is
hotter and drier in some places than in others. The gradual downslope
changes in vegetation reflect the decrease in the amount of soil moisture
available to plants—a condition caused by the decreasing size of soil
particles and consequent shrinkage of water-holding space between particles.
Desert washes encourage plant growth because they channel water and cold
air. Strangely enough, night temperatures are often lower in a desert valley
than farther up the slopes. This “inversion” is due to drainage of cold air
down mountainsides, forming cold “pools” in valley bottoms, especially in
winter. Cold air is heavier than warm, and (since air flows much like water)
it is channeled down the draws—a fact that will strike you if you walk into a
wash near the mountains at night or early in the morning. Add this

phenomenon to the great amounts of moisture that lie beneath the surface of
washes, and you can see that desert drainageways are really linear oases.
More subtly, desert hills reflect in their vegetation the differences in soil
moisture from north slopes to south slopes caused by increasing exposure to
sunlight.

24

One controlling factor, then, is dominant in the desert: the scarcity of 25
water. This results not only in the unusual forms and adaptations of
desert plants, but also in a distinctive type of plant community. In wetter
climes, plants compete mostly for sunlight. They can grow close together, as
long as they receive adequate illumination. During the regrowth of forests,
several distinct sets of plants appear, each succeeding group more tolerant of
shade than the last, as the forest canopy closes. In the desert, there is no such
succession. Clear a patch of desert vegetation, and the same species will
reappear—spaced out, with bare ground between them as before. For here
sunlight is abundant (we might say overabundant), but there is not enough
water to allow plants to cover the ground.

Dr. Forrest Shreve, who was a botanist at the Carnegie Institution’s Desert
Laboratory near Tucson and a master student of deserts, defined a desert as
“an area in which deficient and uncertain rainfall ... has made a strong
impression on the structure, functions, and behavior of living things.” The
distinctive characteristics of desert plants and animals have evolved through
millions of years, in a trial-and-error process in which only the better-fitted
forms have survived. It would be enlightening to know how many of the
species and varieties of plants that developed during the past 60 million
years or so have failed to adapt to Sonoran Desert conditions. It is
fascinating to study the hundreds of forms that have succeeded and to try to
determine what structures they have perfected and what methods they have
originated that enabled them to maintain themselves in such a harsh
environment.

Desert plants can be classified as “escapers,” “evaders,” and “resisters,”
according to their means of adaptation to water shortage. Escapers, such as
the annuals, avoid the problem entirely by waiting out the dry periods as
seeds, to sprout and reproduce only when the rains come. Evaders, such as
the ocotillo, reduce their water loss during droughts by such methods as
dropping their leaves or going into a state of dormancy. Resisters, however,
“hang in there” all year, taking the desert’s worst. The cactuses, prime
examples of this group, rapidly soak up water from each rain and store it for
use during drought; the mesquite’s deep roots tap a more constant source of
moisture.

Succulents

A large group of desert plants conserve water for use in periods of drought
by storing it in specialized tissues during the wet season. Some of these
“succulents,” principally the yuccas, eschevarias, and agaves, have
developed water-storage tissues in their leaves. A few, notably the
NIGHTBLOOMING CEREUS (see appendix for scientific names of plants), have
slender stems but an enormous, carrot-shaped root in which the moisture-
storage tissue is located. The GOURDS also have large, thick, moisture-
retaining roots, as does the WILD-CUCUMBER. 26

The cactuses store water in their stems and thus are called stem succulents.
In the course of its evolution the cactus has eliminated leaves, and their
function has been taken over by the green outer covering of the stems. Thus
the amount of transpiration (moisture loss through plant breathing pores) has
been greatly reduced.

Saguaro buds.

The cactuses are thought to have evolved from relatives of the rose family in
the West Indies, beginning some 18,000 to 20,000 years ago. From there
they spread to most parts of the Western Hemisphere, but particularly to the
drier regions, changing their forms to meet new conditions. One of the
youngest of plant families, the cactuses are still evolving rapidly. This
doesn’t make the task of classifying them easier for the taxonomists.

In varied forms, cactuses enliven the paloverde-saguaro community. In size
they range from tiny button and pincushion types, some of which weigh only
a few ounces, to the giant saguaro, the bulkiest of which may weigh several
tons.

Cactuses as a group are easily recognized, although many people mistakenly
believe that any desert plant with spines or thorns is a cactus. Shreve
describes their main characteristics thus:

Several structural features have served to give the cacti their 27
outstanding appearance, so unlike that of other plants. Most general
have been the loss of the leaf as a permanent organ, the enlargement of the
stem to accommodate water-storing tissue, and the development of local
spinebearing structures known as “areoles.” In several genera, the stem is
segmented into sections which are flat and somewhat leaflike; in others
the stem is round, much branched, and the surface occupied by close-set
tubercles. In a large group, including massive erect forms, as well as
slender climbing ones, the stem is grooved or fluted and thus able readily
to accommodate its surface to great fluctuations in the water content of the
tissues.

If you are trying to identify species, however, cactuses can be annoying,
since they often hybridize. You must expect to find some individuals that
don’t fit the book descriptions.

The Saguaro—Monarch of the Monument

Of all the species of cactus recorded in Saguaro National Monument, the
giant SAGUARO (pronounced sah-WAH-roe) holds the center of interest. From
the visitor’s standpoint, all other plants, no matter how bizarre in appearance
or peculiar in living habits, are merely stage scenery for setting off the star
of the desert drama. For size, this vegetable mammoth tops all other
succulents of this country; heights of more than 50 feet and weights of more
than 5 tons have been reported. There have been specimens with more than
50 arms, or branches. Although no accurate method of determining saguaro
age has been devised, it is estimated that an occasional veteran may reach
the two-century mark.

Structurally, the giant cactus is well adapted to meet the stern requirements
of its habitat. Its widespread root system, as much as 70 feet in diameter,
lying close to the surface of the ground, anchors and holds the heavy plant
erect. The shallow root system quickly and efficiently collects and channels
to the main stem any moisture that may penetrate the topsoil. The trunk and
branches have a cylindrical framework of long slender poles or ribs fused at
the constricted base. This woody skeleton supports the mass of pulpy tissue,
the whole being covered with tough, waxy, spine-bearing “skin.” Numerous
vertical ridges, like the pleats of a huge accordion, permit the stems and
branches to expand in girth as the tissues swell with water during wet
weather and to shrink during times of drought.

So efficient is the saguaro’s water-storage system that, even after years of
extreme drought, the plant retains enough moisture in reserve to enable it to
produce flower buds. The buds appear in vertical rows at the tips of the main
stem and branches, a few opening each evening over a period of several
weeks in May and June. The flowers, up to 4 inches in diameter, have waxy
white petals. This beautiful blossom is the State flower of Arizona. The 28
egg-shaped fruits mature in late June and July, splitting open when ripe
to reveal masses of juicy, deep-red pulp filled with tiny black seeds. Pulp
and seeds are consumed by several kinds of birds, especially white-winged
doves. Many fruits that fall to the ground are promptly eaten by rodents and
other animals.

Indians, too, eat the fruits. European explorers who followed Coronado’s
expedition into this region found peaceful Papagos and Opatas living here,
hunting animals and utilizing many native plants. Among the most

dependable of Papago food sources was the fruit of the giant cactus. So
important was this fruit harvest in their economy that they designated this
season as the start of the new year. Today, in some parts of the desert, Pima
and Papago Indians still harvest the fruits. The word “saguaro” is believed to
derive from a Spanish corruption of a Papago word for the big cactus.

Spiny armor of the saguaro.

Saguaro in full bloom.

Saguaros provide not only food for man and beast, but homes for animals.
Walk through a giant cactus forest and you will be amazed at the 29
number of holes drilled in these plants. The holes are made by Gila
woodpeckers and related gilded flickers, which often relinquish them after
one nesting season. The next occupant may be any of a host of desert
dwellers, including screech and elf owls, purple martins, and invertebrates.
Some birds use the plant as a foundation for their homes. White-winged
doves, for instance, often build flimsy stick platforms on the tips of saguaro

arms; red-tailed hawks and horned owls construct more substantial nests in
the forks.

Although billions of saguaro seeds are produced yearly in the extensive
stands of the monument, only a very few find favorable locations for
germination and growth. Trees, rocks, dead limbs, pebbles—anything that
reduces evaporation in the immediate vicinity of the seed—improve the
chance of germination. These kinds of shelter not only provide the necessary
moisture conditions, but also hide the seed from armies of ants, rodents, and
other animals searching for food.

Saguaro blossoms.

Saguaro fruit.

Early growth is extremely slow. A 2-year-old saguaro may be only one- 30
quarter of an inch in diameter, and a 9-year-old plant may be 6 inches
high. These years are the most hazardous. Insect larvae devour the tiny
cactuses. Woodrats and other rodents chew the succulent tissue for its water,
and ground squirrels uproot the young plants with their digging. In later life,

the saguaro must contend with uprooting wind and human vandalism, as
well as the earlier foes—drought, frost, erosion, and animals.

Gila woodpecker at its nesting hole.

In a century of maturity, a saguaro may produce 50 million seeds;
replacement of the parent plant would require only that one of these
germinate and grow. But in the cactus forest of the Rincon Mountain
Section, the rate of survival has been even lower, so that over the last few
decades the stand has been dwindling. What is wrong?

Many answers to this question have been advanced, but like all
interrelationships in nature, the saguaro’s role in the desert web of life is
very complex, and involves past events as well as present ones; a partial
answer to the problem may be all we can hope for. The following reasons for
the decline of the saguaros have been suggested by researchers.

31

Saguaro, 1 foot high, in a rocky habitat.

A typical 4-foot saguaro.

There is some evidence to suggest that the Southwest has been getting drier
since at least the late 19th century, and while the saguaro is adapted to
extreme aridity, some of the “nurse” plants that shelter it during infancy are
not. If such shrubs as paloverdes and mesquites dwindle, it is argued, so
must the saguaro, which in its early years depends on them for shade.

Other culprits in the saguaro problem are man himself and his livestock.
Around 1880, soon after the first railroad reached Tucson, a cattle boom
began in southern Arizona. The valleys were soon overstocked, and cattle

scoured the mountainsides in search of food. By 1893, when drought and
starvation decimated the herds, the land had been severely overgrazed.
Though the monument was established in 1933, grazing in the Rincon
Mountain Section’s main cactus forest continued until 1958. (Elsewhere in
the monument, it still goes on.) Compounding the problem, woodcutters
removed acres of mesquite and other trees. In the center of the present
Cactus Forest Loop Drive, lime kilns devoured quantities of woody fuel.
Further upsetting the desert’s natural balance, ranchers and Government
agents poisoned coyotes and shot hawks and other predators—in the 32
belief that this would benefit the owners of livestock.

This unrestrained assault on the environment had unfortunate effects on
saguaros as well as on the human economy. Overgrazing may have resulted
in an increase in kangaroo rats (which benefit from bare ground on which to
hunt seeds) and certain other rodents adapted to an open sort of ground
cover. Man’s killing of predators, their natural enemies, further encouraged
proliferation of these rodents, which some people say are especially
destructive of saguaro seeds and young plants. Whatever the effect these
rodents have on the saguaros, the removal of ground cover intensified
erosion and reduced the chances for the seeds to germinate and grow. And
certainly the cutting of desert trees removed shade that would have benefited
young saguaros. In the Tucson Mountain Section, which is near the
northeastern edge of the Sonoran Desert, freezing temperatures are perhaps
the most important environmental factor in saguaro mortality.

Looking toward the Santa Catalina Mountains from Cactus Forest
Drive in September 1942.

Although the causes of decline of the cactus forest lying northwest of
Tanque Verde Ridge are still something of a puzzle, several facts are clear:
the saguaro is not becoming extinct; in rocky habitats many young saguaros
are surviving, promising continued stands for the future; in non-rocky
habitats, some young saguaros are surviving, ensuring that at least thin
stands will endure in these areas. Furthermore, since grazing was 33
stopped here, ground cover has improved—a plus factor for the
saguaro’s welfare. On the negative side, it is possible that, in addition to
suffering from climatic, biotic, and human pressures, the once-dense mature
stands of the monument are in the down-phase of a natural fluctuation. It is
possible, too, that these stands owed their exceptional richness to an
unusually favorable past environment which may not occur again. We can
hope, however, that sometime in the not-distant future the total
environmental balance will shift once again in favor of the giant cactus.

A photograph taken from the same spot in January 1970.

Other Common Cactuses

Many other cactuses share the saguaro’s environment. The BARREL CACTUS is
sometimes mistaken for a young saguaro, but can easily be distinguished by
its curved red spines. Stocky and unbranching, this cactus rarely attains a
height of more than 5 or 6 feet. It bears clusters of sharp spines, called
“areoles,” with the stout central spine flattened and curved like a fishhook.
In bloom, in late summer or early autumn, this succulent plant produces
clusters of yellow or orange flowers on its crown. The widely circulated
story that water can be obtained by tapping the barrel cactus has little basis
in fact, although it is possible that the thick, bitter juice squeezed from the
plant’s moist tissues might, under extreme conditions, prevent death from
thirst. Desert rats, mice, and rabbits, carefully avoiding the spines, 34
sometimes gnaw into the plant’s tissues to obtain moisture.

The group of cactuses called opuntias (oh-POON-cha) have jointed stems and
branches. They are common and widespread throughout the desert and are
well represented in the monument.

Those having cylindrical joints are known as chollas (CHO-yah), while those
with flat or padlike joints are called pricklypears.

Chollas range in size and form from low mats to small trees, but most of
those in the monument are shrublike. TEDDY BEAR CHOLLA, infamous for its
barbed, hard-to-remove-from-your-skin spines, forms thick stands on warm
south- or west-facing slopes. Its dense armor of straw-colored spines and its
black trunk identify it. Because its joints break off easily when in contact
with man or animal, this uncuddly customer is popularly called “jumping
cactus.” A similar species is CHAIN FRUIT CHOLLA, notable for its long,
branched chains of fruit, which sometimes extend to the ground. Each year,
the new flowers blossom from the persistent fruit of the previous year. There
is a common variety of this species that is almost spineless. STAGHORN
CHOLLA, an inhabitant primarily of washes and other damp places, is named
from its antler-shaped stems. This cactus’ scientific name—Opuntia
versicolor—refers to the fact that its flowers, which appear in April and
May, may be yellow, red, green, or brown. (Each plant sticks with one color
through its lifetime.) Among the smaller chollas, thin-stemmed PENCIL
CHOLLA grows from 2 to 4 feet high on plains and sandy washes. DESERT
CHRISTMAS CACTUS, almost mat-like in form, blooms in late spring but
develops brilliant red fruits which last through the winter.

Barrel cactus blossoms.

Barrel cactus spines.

35

Chain fruit cholla at Tucson Mountain Section headquarters.

PRICKLYPEARS, like many of the chollas, produce large blossoms in late 36
spring. Those on the monument are principally the yellow-flowered
species. The reddish brown-to-mahogany colored edible fruits, called tunas,
attain the size of large strawberries. When mature in autumn, they are
consumed by many desert animals.

Some of the smaller cactuses are so tiny as to be unnoticeable except when
in bloom; examples are the HEDGEHOGS, the FISHHOOKS, and the PINCUSHIONS.
Blossoms of some of these ground-hugging species are large, in some cases
larger than the rest of the plant, and spectacular in form and color. All add to
the monument’s spring and early summer display of floral beauty.

Non-Succulents

For the diversity of devices for adaptation to an inhospitable environment,
the many species making up the non-succulent desert vegetation provide an
absorbing field for study. As we have seen, there are two ways to survive the
harsh desert climate; one is to avoid the periods of excessive heat and
drought (“escapers”); the other is to adopt various protective devices
(“evaders” and “resisters”). Short-lived plants follow the first method;
perennials, the second.

Perennials

Chief among the requirements for year-round survival in the desert is a
plant’s ability to control transpiration and thus maintain a balance between
water loss and water supply. In this struggle, the hours of darkness are a
great aid because in the cool of the night the air is unable to take up as much
moisture as it does under the influence of the sun’s evaporating heat.
Therefore, less exhaling and evaporating of water occurs from plants, and
both the rate and the amount of water loss are reduced. This reduction in
transpiration at night allows the plants to recover from the severe drying

effects of the day. One biologist may have been close to the truth when he
stated, “If the celestial machinery should break down so that just one night
were omitted in the midst of a dry season, it would spell the doom of half the
nonsucculent plants in the desert.”

One of the common trees in the desert part of the monument is the MESQUITE
(mess-KEET). In general appearance it resembles a small, spiny apple or
peach tree with finely divided leaves. Its roots sometimes penetrate to a
depth of 40 or more feet, thus securing moisture at the deeper, cooler soil
levels, from a supply that remains nearly constant throughout the year. This
enables the tree to expose a rather large expanse of leaf surface without
losing more water than it can replace. A number of mechanical devices help
the tree reduce its water loss during the driest part of the day (10 a.m. to 4
p.m.). Among these are its ability to fold its leaves and close the stomata
(breathing pores), thereby greatly reducing the surface area exposed to 37
exhaling and evaporating influences. In April and May, mesquite trees
are covered with pale-yellow, catkinlike flowers which attract swarms of
insects. These flowers develop to stringbeanlike pods rich in sugar and
important as food for deer and other animals. In earlier days, the mesquite
was also a valuable source of food and firewood for Indians and pioneers.

Pricklypear blossom.

Claret cup hedgehog.

Fishhook cactus.

Cholla in bloom.

Staghorn cholla.

Another desert tree abundant in the monument is the YELLOW PALOVERDE. It
is somewhat similar in size and general shape to the mesquite. Lacking the
deeply penetrating root system of the mesquite, the paloverde (Spanish word
meaning “green stick”) has no dependable moisture source; but it has made
unusual adaptations that enable it to retain as much as possible of the water
collected by its roots. In early spring the tree leafs out in dense foliage,
which is followed closely by a blanket of yellow blossoms. At this season

the paloverdes provide one of the most spectacular displays of the desert,
particularly along washes, where they grow especially well. Blue 38
paloverde, growing in the arroyos, blooms well every year. Yellow, or
foothill, paloverde, a separate species, blooms only if the soil moisture is
high following winter rains.

With the coming of the hot, drying weather of late spring, the trees need to
reduce their moisture losses. They gradually drop their leaves until, by early
summer, each tree has become practically bare. The trees do not enter a
period of dormancy, but are able to remain active because their green bark
contains chlorophyll. Thus, the bark takes over some of the food-
manufacturing function normally performed by leaves, but without the high
rate of water loss.

Carrying the drought-evasion habits of the paloverde a step further, the
OCOTILLO (oh-koh-TEE-yoh) comes into full leaf following each rainy spell
during the warmer months. During the intervening dry periods it sheds its
foliage. The ocotillo, a common and conspicuous desert dweller, is a shrub
of striking appearance, with thorny, whiplike, unbranching stems 8 to 12 feet
long growing upward in a funnel-shaped cluster. In spring, showy scarlet
flower clusters appear at the tips of the stems, making each plant a glowing
splash of color.

Mesquite in bloom.

A number of desert shrubs fail to display as much ingenuity as the paloverde.
Some of these evade the dry season simply by going into a state of
dormancy. The WOLFBERRY bursts into full leaf soon after the first winter
rains and blossoms as early as January. Its small, tomato-red, juicy fruits are
sought by birds, which also find protective cover for their nests and for
overnight perches in the stiff, thorny shrubs. In the past, the berrylike fruits
were important to the Indians, who ate them raw or made them into a 39
sauce.

Yellow paloverde, Tucson Mountain Section.

Commonest of the conspicuous desert non-succulent shrubs is the wispy-
looking but tough CREOSOTEBUSH, found principally on poor soils and on the
desert flats between mountain ranges. It is also sprinkled throughout the
paloverde-saguaro community in the monument. A new crop of wax-coated,
musty-smelling leaves, giving the plant the local (but mistaken) name
“grease-wood,” appears as early as January. The leaves are followed by a
profuse blooming of small yellow flowers and cottony seed balls. During
abnormally moist summers or in damp locations, the leaves and flowers
persist the year round; but usually the coming of dry weather brings an 40
end to the blossoming period. If the dry spell is exceptionally long, the
leaves turn brown, and the plants remain dormant until awakened by the next
winter’s rainfall. Pima Indians formerly gathered a resinous material, known
as lac, which accumulates on the bark of its branches, and used it to mend
pottery and fasten arrow points. They also steeped the leaves to obtain an
antiseptic medicine. Ground squirrels commonly feed on the seeds.

Ironwood blossoms.

Parry’s penstemon.

A large shrub of open, sprawling growth usually found along desert washes
in company with mesquite is CATCLAW. Its name refers to the small curved
thorns that hide on its branches. In April and May, the small trees are
covered with fragrant, pale-yellow, catkinlike flower clusters that attract
swarms of insects. The seed pods were ground into meal by the Indians and
eaten as mush and cakes.

In lower elevations of the Tucson Mountain Section, the gray-blue foliage of
IRONWOOD is a common sight, but the species does not range farther
eastward. Its wisterialike lavender-and-white flowers blossom in May and
June. The nutritious seeds are harvested by rodents and formerly were
parched and eaten by Indians. The wood is so dense that it sinks in water;
Indians used it for making arrowheads and tool handles.

Ferns—commonly, plants of dank woods and other moist habitats—seem
entirely out of place in the desert; nevertheless, some members of the fern
family have overcome drought conditions. The GOLDFERN is common on
rocky ledges, where it persists by means of special drought-resistant cells.

Among the smaller perennials are many that add to spring flower displays
when conditions of moisture and temperature are favorable. Perennials 41
do not need to mature their seeds before the coming of summer as do
the ephemerals; a majority start blossoming somewhat later in the spring,
and gaily flaunt their flowers long after the annuals have faded and died.
When the heat and drought of early summer begin to bear down, they
gradually die back, surviving the “long dry” by their persistent roots and
larger stems. One of the most noticeable and beautiful of this group of small
perennials fairly common in the monument is PARRY’S PENSTEMON. It occurs
in scattered clumps on well-drained slopes along the base of Tanque Verde
Ridge. The showy rose-magenta flowers and the glossy-green leaves arise
from erect stems that may grow 4 feet tall in favorable seasons.

Among the first of the shrubby perennials to cover the rocky hillsides with a
blanket of winter and springtime bloom is the BRITTLEBUSH. Masses of
yellow sunflowerlike blossoms are borne on long stems that exude a gum
which was chewed by the Indians and was also burned as incense in early
mission churches.

A conspicuous perennial that survives the dry season as an underground bulb
is BLUEDICKS. Although it doesn’t occur in massed bloom, it does add spots
of color to the desert scene. Usually appearing from February to May,
bluedicks has violet flower clusters on long, slender, erect stems. The bulbs
were dug and eaten by Pima and Papago Indians.

Although neither conspicuous nor attractive, the common TRIANGLE BURSAGE
is an important part of the paloverde-saguaro community in the Tucson
Mountains. A low, rounded, white-barked shrub, bursage has small, colorless
flowers without petals. (Being wind-pollinated, the flowers do not need to
attract insects.)

One of the handsome shrubs abundant in the high desert along the base of
Tanque Verde Ridge is the JOJOBA (ho-HOH-bah), or deernut. Its thick,

leathery, evergreen leaves are especially noticeable in winter and furnish
excellent browse for deer. The flowers are small and yellowish, but the
nutlike fruits are large and edible, although bitter. They were eaten raw or
parched by the Indians, and were pulverized by early-day settlers for use as a
coffee substitute.

Among the attractive flowering shrubs are the INDIGOBUSHES, of which there
are several species adapted to the desert environment. The local, low-
growing indigobushes are especially ornamental when covered with masses
of deep-blue flowers in spring.

Another small shrub, noticeable from February to May because of its large,
tassel-like pink-to-red blossoms and its fernlike leaves is FAIRY-DUSTER. Deer
browse on its delicate foliage.

The PAPER FLOWER, growing in dome-shaped clumps covered with yellow
flowers, sometimes blooms throughout the entire year. The petals bleach and
dry and may remain on the plant weeks after the blossoms have faded.

Quick to attract attention because of their apparent lack of foliage, the 42
JOINTFIRS, of which there are several desert species, grow in clumps of
harsh, stringy, yellow-green, erect stems. The skin or outer bark of the stems
performs the usual functions of leaves, which on these plants have been
reduced to scales. Small, fragrant, yellow blossom clusters, appearing at the
stem joints in spring, are visited by insects attracted to their nectar.

Ephemerals

Every spring, after a winter of normal rainfall, parts of the southwestern
deserts are carpeted with a lush blanket of fast-growing annual herbs and
wildflowers—the early spring ephemerals. The monument does not get
massive displays, however, since it is lacking in the species that make the
best show. But it does have many annuals that are beautiful individually or in
small groups. Many of these “quickies” do not have the characteristics of
desert plants; some of them, in fact, are part of the common vegetation of

other climes where moisture is plentiful and summer temperatures are much
less severe.

What are these “foreign” plants doing in the desert, and how do they
survive? With its often frostfree winter climate and its normal December-to-
March rains, the desert presents in early spring ideal growing weather for
annuals that are able to compress a generation into several months. Several
hundred species of plants have taken advantage of this situation.

There is WILD CARROT, which is a summer plant in South Carolina and a
winter annual in California (where it is called “rattlesnake weed”). In the
desert, its seeds lie dormant in the soil through the long, hot summer and the
drying weather of autumn. Then, under the influence of winter rains and the
soil-warming effects of early spring sunshine, they burst into rapid growth.
One of a host of species, this early spring ephemeral is enabled by these
favorable conditions to flower and mature its seed before the pall of summer
heat and drought descends upon the desert. With their task complete, the
parents wither and die. Their ripened seeds are scattered over the desert until
winter rains enable them to cover the desert with another multicolored but
short-lived carpet of foliage and bloom.

The one-season ephemerals do not limit themselves to the winter growing
period. From July to September, local thundershowers deluge parts of the
desert while other areas, not so fortunate, remain dry. Where rain has fallen,
another and entirely different group of plants, called the summer ephemerals,
find ideal conditions for growth and take their turn at weaving a desert
carpet. Their seeds have lain dormant over winter. These summer “quickies”
are plants that, farther south in Baja California and Sonora, Mexico, flourish
during the winter rainy season. Saguaro National Monument is doubly 43
fortunate in that it lies within a section of desert having not only its
own year-round vegetation, but also summer wildflowers “borrowed,” for
winter use, from its eastern and western neighbors, and winter wildflowers
for summer decorations from its southern neighbors.

Phacelia, an ephemeral.

The short-lived leafy plants of summer and winter are able to compress their
entire active life into 6 to 12 weeks when conditions are most suitable. Thus,
they can escape all the rigorous periods of the desert climate by living for 8
or 9 months in the dormant seed stage. Some of the spectacular and colorful
flowers of the monument are among these ephemerals that survive desert
conditions by escaping them. It must be remembered, however, that 44
when drought conditions or abnormally cold spring weather upset the
norm—a not unusual occurrence—response of ephemeral plants is greatly
restricted. If suitable conditions do not develop during the season for growth
of a particular kind of ephemeral, its seeds will simply wait a year or more
until conditions are favorable.

White tackstem.

How do the seeds of ephemerals “know” when it is time to germinate?
Experiments have revealed that the seeds of annuals will germinate only
when enough water percolates through the soil to dissolve away a “growth
inhibitor” in their coats. A single light rain will not do the job. In this way

premature sprouting into a too-dry environment is prevented. The winter
annuals, furthermore, will only germinate when soils are cool, and the
summer annuals when soils are warm. These finely tuned adaptations thus
allow plantlife to take full advantage of favorable seasons in the desert.

Early spring ephemerals climax their show in March. From late February to
mid-April they are completing their growth and putting forth the precious
seeds that will assure survival for the next generation. At the head of this
parade of flowers in the monument is a purple-blossomed immigrant from
the Mediterranean, the now thoroughly naturalized FILAREE. In addition to
the small purple flowers, which may appear as early as January, the
conspicuous “tailed” fruits almost always attract attention. When dry, they
are tightly twisted, corkscrewlike; when damp they uncoil, forcing the 45
needle-tipped seeds into the soil.

Desert-marigold.

INDIAN WHEAT is one of the first plants to lay a green carpet over the sandy
desert floor in spring. The tan, individual flower heads are conspicuous, but
their numerous, close-growing spikes form a thick, luxuriant, pilelike ground
cover. The countless tiny seeds are eagerly sought each spring by coveys of
Gambel’s quail, and are also harvested by Pima and Papago Indians.

DESERT CHICORY is somewhat like the common yellow dandelion but is
longer stemmed and less coarse. Its white or butter-yellow blossoms make it
one of the noticeable spring annuals in the desert. It rarely grows in pure
stands but appears in conspicuous clumps among other short-lived plants.

Somewhat similar in appearance to desert chicory is WHITE TACKSTEM, one of
the handsomest of the spring quickies. It is usually found on dry, rocky
hillsides and has white or rose-colored flowers. Its name is derived from the
presence of small glands which protrude in the manner of tiny tacks partially
driven into the stems.

Following abnormally wet winters, FIDDLENECK covers patches of sandy or
gravelly soil with a dense growth of bristly erect plants. These bear tight
clusters of small yellow-orange blossoms arranged along a curling flower
stem resembling the scroll end of a violin, hence the name. This plant,
favored by the same growing conditions as creosotebush, frequently forms a
dense though short-lived growth around the bases of those shrubs.

Associated with fiddleneck and creosotebush, SCORPIONWEED adds its 46
violet-purple blooms to the spring flower display following winters of
above-normal precipitation. The name is derived from the curling habit of
the blossom heads, which may remind the observer of the flexed tail of a
scorpion. Touching the plant may cause skin irritation in susceptible
individuals. Unfortunately, scorpionweed is also widely known as wild-
heliotrope, thus contributing to the confusion engendered by duplication of
popular names. The plant properly called WILD-HELIOTROPE is similar in
general appearance, but the flowers are white to pale purple and their odor is
more pleasing than that of the scorpionweed. Wild-heliotrope, or
“quailplant,” is another of the early spring ephemerals, but under favorable
conditions, where soils are moist, it may continue to live and bloom
throughout the year.

Bladder-pod.

Growing in sandy locations and quite noticeable because of its large, yellow,
showy, long-stemmed flower heads, the DESERT-MARIGOLD helps to open the
spring blossoming season. Where moisture conditions are favorable, these
plants may continue to bloom throughout the summer and well into autumn.
Sometimes, during the hottest, driest time of the year, desert-marigolds are
among the very few blossoms brightening the desert floor. Their 47
bleached, papery petals persist for days after the flowers have faded,
giving the plant the name paper-daisy.

One of the few species that makes a carpet of color in the monument is the
tiny BLADDER-POD. This low-growing annual of the mustard family begins to
cover open stretches of desert with a yellow blanket in late February or early
March following wet winters. Bladder-pod is usually found in pure stands
surrounding islands of cholla, creosotebush, and paloverde. It also mingles

with other spring ephemerals, where it is promptly submerged by the ranker,
taller-growing, more conspicuous annuals.

Illustrating one of the interesting phases in evolutionary variations among
plants, the LUPINES are represented by several species which are able to
survive and prosper in the desert. Some of the lupines are annuals of the
quickie type; others are perennials with a life cycle of several years. Some of
these longer-lived species join the ephemerals in the spring flower show,
while others are more leisurely in approaching their blossoming time.

48

The Desert Scrub Community occupies the lower parts of the
monument, from about 2,200 to 4,000 feet.

The Grassland Transition begins at about 3,500 feet (overlapping in
altitude with the Desert Scrub) and extends to 4,500 feet.

49

major plant communities
of saguaro

SAGUARO NATIONAL MONUMENT

Tucson Mountain Section
Biotic Communities

Desert Scrub
Grassland
Transition

In any region where a great range of altitude exists, the vegetation grows in a
continuum of overlapping but recognizable zones. Climate being the major
controlling factor of this zonal distribution, the plants of each band grow
higher on south-facing slopes than on cooler, moister north slopes. In
Saguaro the major plant communities roughly correspond to altitudinal
bands—with the desert at the lower, drier levels, and the transition through
grasses and shrubland to forest community occurring with increasing 50
altitude (and increasing rainfall). Timberline—the boundary between
high mountain forests and the alpine meadows and barrens—does not exist
in Saguaro, where trees clothe the highest peaks.

The fauna of each community is made up of animals adapted to the climatic
conditions and the available food, cover, and water. In Saguaro, some
animals, such as the desert kangaroo rat and the cactus wren, are restricted
by their life requirements to a narrow belt; others, such as the gray fox and
great horned owl, are more adaptable and live in all the major plant
communities.

SAGUARO NATIONAL MONUMENT

Rincon Mountain Section
Biotic Communities

Desert Scrub
Grassland Transition
Oak Woodland
Oak-Pine Woodland
Ponderosa Pine Forest
Douglas-fir Forest

52

The Open Oak Woodland has scattered trees associated with many
plants of the Grassland Transition.

The Oak-Pine Woodland, from 4,500 to 7,000 feet, occupying a slightly
cooler, wetter environment than those below, is broken by open glades
and grassy hillsides.

53

The Ponderosa Pine Forest, unlike the Oak-Pine “pygmy woodland,”
has tall trees growing in clear, open stands. It covers much of the
Rincon Mountains above 6,000 feet.

The Douglas-fir Forest, limited to the higher northern and northeastern
slopes of Mica Mountain and the north side of Rincon Peak, often
contains aspens and white firs.

54

Spanish dagger, with Rincon Peak in the background.

55

plants of the hills
and mountains
Most visitors to the monument see only a small part of it—the lowland
cactus forests. But above the desert in the high back country of the Rincon
Mountains is another world. These highlands are accessible only on foot or
horseback; and they should remain so, for they are now in the last major
roadless range in southern Arizona, and as such their wilderness value
appreciates yearly. Interesting scenic trails reach the high places of the
Tucson Mountains, too, but to see the greatest changes in plantlife you must
climb the higher Rincons.

Oak-Pine Woodland

The thinning and final disappearance of saguaros along the trailside,
although mesquite and ocotillos seem almost as numerous as on the floor of
the desert, indicate that you are entering a slightly cooler, wetter
environment. An occasional MEXICAN BLUE OAK or ARIZONA ROSEWOOD
appears among the mesquites along the washes. The grasses that
increasingly cover the ground as you climb include HAIRY, SIDEOATS, and
SPRUCETOP GRAMA; CURLY MESQUITEGRASS; TANGLEHEAD; TEXAS BLUESTEM;
and WOLFTAIL. Mingling with them are TURPENTINE-BUSH and shrubby
SNAKEWEED.

A spectacular inhabitant of the grassland transition and open oak woodlands
you are now entering is the AMOLE, or SHINDAGGER, whose rapidly growing
blossom stalks attract attention from May to as late as August. The plants

themselves, which grow crowded together in patches, consist of rosettes of
succulent leaves superficially resembling bunches of flattened, green
bananas. The stiff, needle-sharp leaf tips can inflict painful jabs on man and
beast. During its lifetime, the plant stores food in its short, thick stem.
Finally, after several years, it sends up an unbranched flower stalk that grows
to 5 feet. The light-yellow flowers mature to brown, capsule-like fruits, after
which the plant dies. The short stems or crowns, containing saponin, were
used by Indians as soap. They also roasted the young bud stalks of some
species by covering them with heated stones in pits.

Two noticeable plants of the lily family which sometimes dominate gravelly
slopes of the grassland-oak woodland belt are the SOTOL and BEARGRASS, or
sacahuista. The former grows from a compact crown as a dense, rather 56
symmetrical cluster of long, thin ribbonlike leaves, usually grayed at
the tips and armed along the margins with curved thorns. In early summer
many small, cream-colored blossoms develop along the upper extremity of
single fast-growing flower stalks 8 to 10 feet high. The bud stalks formerly
were harvested and roasted by Indians. In Mexico a potent alcoholic drink,
sotol, is distilled from the fermented juice of the pounded crowns.
Sacahuista resembles huge, sprawling clusters of coarse grass. Flower stalks
are short, producing conspicuous, open, loose sprays of small, tan-to-
brownish flowers in May and June. Indians used the tender bud stalks for
food and obtained fiber from the long, slender leaves, weaving them into
baskets and mats.

Mexican blue oak foliage.

Uncommon in the monument, but worthy of mention, are ARIZONA SYCAMORE
and ARIZONA CYPRESS. The latter is restricted to the east flank of the Rincon
Mountains, steep slopes, and deep canyons, where it grows with the
SILVERLEAF, PALMER, EMORY, and NETLEAF OAKS; mesic shrubs; poison oak;
and CALIFORNIA BUCKTHORN. Arizona sycamore grows along lower-canyon
watercourses such as Chiminea and Rincon Creeks, which drain the rugged
south flank of Mica Mountain and the west flank of Rincon Peak,
respectively.

As you continue to climb, the open, grassy, shrub-dotted slopes change in
places to sprawling thickets, called chaparral. These are made up of
manzanita and skunkbush, SILKTASSEL, evergreen oaks, and underbrush of
smaller shrubs. Among the common oaks are ARIZONA WHITE OAK and, on
drier sites of the Tanque Verde range, SHRUB LIVE OAK. The oaks furnish
protective cover, browse, and acorns for deer and other mammals and birds,
and are of great value in retarding soil erosion on steep gravelly slopes.

57

Turpentine-bush, a member of the sunflower family.

POINTLEAF MANZANITA is especially abundant on the lower eastern flanks of
the Rincon Mountains in the Happy Valley area. Early in spring the waxy,
urn-shaped blossoms, the leathery, glossy, evergreen leaves, and the typical
grotesquely crooked, red-barked limbs, make manzanita one of the most
attractive shrubs of the chaparral.

Although SKUNKBUSH is a close relative of poison ivy and sumac, its
aromatic foliage is harmless. Growing in compact thickets, skunkbush
provides food and cover for birds and other small animals. Inconspicuous
yellow flowers appear from March to June, and are followed by berrylike
fruits which are dull red when mature.

As you follow the trail higher, occasional MEXICAN PINYON PINES and
ALLIGATOR JUNIPERS appear. Gradually these evergreens become more

abundant, mingling with the oaks to form a pigmy oak-pine-juniper forest.
Clumps of MOUNTAIN-MAHOGANY are noticeable, their feathery seed “tails”
gleaming in the sunshine.

Pinyons are among the commonest and most widespread trees of the middle
elevations throughout the Southwest. The Mexican pinyon, which is the
species growing abundantly in the Tanque Verde-Rincon upland, may be
recognized by the fact that its foliage is in clusters of three needles to the
bundle. Its cones require nearly 2 years to mature and contain hard-shelled
seeds or nuts which are a source of food for many birds and mammals.
These pines are usually shrubby, rarely more than 15 to 25 feet high, with
horizontal, twisted, low-growing limbs. Intermingled with the pinyons are
alligator junipers, often mistakenly called cedars. Those in the monument are
conspicuous because their platy bark forms an attractive pattern 58
resembling the squarish-scaled skin of alligators. The berrylike cones
are soft and mealy, and are eaten by many kinds of wild animals.

Although the oak-pine woodland supports a heavy stand of shrubby trees
over much of the terrain, there are numerous open glades and grassy
hillsides. In addition to some of the aforementioned grasses, BLUEGRASS,
BULLGRASS, and PLAINS LIVEGRASS provide ground cover in this belt.
Following summer showers, many flowering herbs brighten the open slopes.
Yellow to orange petals of PUCCOON, and the white to lavender-and-rose
blossoms of MOCK-PENNYROYAL and HOUSTONIA are among those seen along
the trailside.

Ponderosa Pine Forest

Just as grassland merges with oak woodland and chaparral, and these with
oak-pine woodland, so you will notice, as you climb steadily higher, that
these woodlands gradually mingle with the open pine forests that cover
much of the Rincon Mountains above 6,000 feet. PONDEROSA PINE is the “big
tree” of the Rincons, usually growing in clear, open stands. Through its high
canopy of spreading branches, sunlight mottles the shaded forest floor. Its
presence indicates still cooler and wetter conditions than those below. Here
you will need blankets at night, though summer days are warm.

Except for grasses such as PINE DROPSEED, SCREWLEAF MUHLY, and MOUNTAIN
MUHLY, ground cover is scarce. In tree-glades or on old burns, however,
intermediate-type shrubs (such as BUCKBUSH) and various herbs have
established themselves. Some herbs develop into patches of colorful flowers
in summer and autumn. Common flowering plants found among the pines
are COLOGANIA; PEAVINE, with its large and showy, white, sweetpea-like
blossoms throughout the summer; lupines; DOGBANE; and the familiar white
WESTERN YARROW. Here, too, may be found GROUNDSEL, ASTER, FLEABANE,
and others, often brightened by the presence of butterflies and other insects
seeking nectar and pollen. Most of these forest flowers bloom in late
summer or autumn, when plants in the desert, far below, are drab and
dormant.

Throughout the pine forests, numerous small canyons and rocky outcrops
favor the development of thickets of oak and locust, frequently growing
together. GAMBEL’S OAK, a leaf-shedding white oak, ranges in size from a
small shrub to a handsome tree. It has broad, deeply lobed leaves which
provide browse for deer. Its acorns are consumed by deer, rodents, and birds,
including wild turkeys. The NEW MEXICAN LOCUST also is browsed by deer.
Rarely reaching tree size, this species is an attractive vegetative cover
because of its odd-pinnate leaves and large clusters of purplish-pink flowers
that appear in May and June. Locusts sprout freely from roots and form 59
expanding thickets which encroach upon oak clumps. They provide a
valuable network of soil-holding roots, important in retarding erosion. The
best stands occur along the east slopes of the Rincons.

Relatively few in number, compared with the stands of the dominant
ponderosa pine, the smaller CHIHUAHUA PINE grows on lower dry slopes and
benches. Its needles are shorter than those of the ponderosa pine, and its
cones are conspicuously persistent, remaining on the tree for several years.
This Mexican species invades the United States in the mountain ranges of
southern Arizona and southwestern New Mexico. In the monument it is
found mostly in the transition areas between oak-pine woodland and
ponderosa pine forest.

The Rincon Mountains are not high enough to provide a fir-forest habitat
except in a few favorable locations. On the highest parts of the Rincons,
ponderosa pines dominate in the warmer, exposed locations, but whitebarked

QUAKING ASPENS grow in pure stands on cooler slopes and with DOUGLAS-FIRS
on the north side of Rincon Peak. West of Spud Rock are abundant small
groves of MEXICAN WHITE PINE.

A cone-bearing tree growing with Douglas-fir—exclusively on higher
northern and northeastern slopes of Mica Mountain—is the WHITE FIR.
Flattened, gray-green needles curving upward from the branches, and large,
green cones growing upright on limbs near the tops of the trees identify this
beautiful evergreen. On open stands, limbs of even the large trees grow from
the trunk almost down to the ground. The bark is gray or ash-colored.

BRACKEN forms a green ground cover in heavy stands of pine and fir. This
fern grows 3 feet tall over much of the forested Rincon highland. Among the
shrubs found on the mountaintop is the SNOWBERRY, whose leaves are
browsed by deer and whose berries are eaten by birds and chipmunks.

A spring, a small mountain stream, and a meadow near Manning Camp
complete the picture of the higher elevations in the monument. In this bit of
meadowland are found BOXELDER, NEW MEXICAN ALDER, CINQUEFOIL,
CHOKECHERRY, GOLDENROD, ORANGE SNEEZEWEED, MARIGOLD, WILLOW, and a
number of other shrubs, grasses, and herbs characteristic of the high
mountain meadows of the Southwest.

60

Jerusalem cricket (of a different family from the true crickets) has legs
adapted for tunneling in sand.

61

animals
and how they survive
Just as plants depend for their existence on soil, water, and sunlight, so
animals, including man, depend on plants. For green plants are the basic
food producers in nature, manufacturing carbohydrates, proteins, and other
essential compounds from minerals, air, and water, with the help of
chlorophyll and the sun’s energy. Animals get their food either by eating
green plants or by eating animals that have eaten plants. Microscopic
decomposers complete this food chain, breaking down dead plants and
animals into substances that once again can be used by plants. Since each
link in the chain depends on the other links, it’s not hard to see that a change
in one will cause a change in the others. And because animals depend on
plants for cover as well as for food, their fortunes are doubly tied to the
welfare of plants.

Animals and plants share some of the same basic problems—particularly,
how to stay within tolerable temperature limits, and how to maintain an
adequate supply of water. Plants solve these problems mostly by structural
adaptations, animals mostly by behavioral. In the desert, for instance, cold-
blooded animals such as snakes and lizards (which have no internal control
over body temperature) crawl underground or into shade during the midday
heat of summer, and come out to hunt food during the cooler hours. Birds
and mammals cool themselves through evaporation of water from their
bodies. This makes water conservation doubly critical for them; they too
handle it by staying in the shade or going underground during hot times.
Desert animals get much of their water from the plants and animals they eat,
but some species, such as mule deer and Gambel’s quail, require large
amounts of drinking water as well.

Cold weather poses another problem. Most reptiles and some mammals
solve this one by hibernating underground or in rock dens, where
temperatures remain moderate throughout the year. Many birds and some
mammals migrate to areas where temperatures are warmer and food is more
abundant, which may mean going farther south or simply moving down the
mountainsides. And insects can survive in a dormant form, as eggs or pupae,
though many species remain active during the temperate Sonoran winters.

If you want to see animals, then, go where the vegetation is thickest 62
and most varied, and go when temperatures are moderate. During
warm seasons in the desert, this means that walking the washes early or late
in the day will give you the best chances for seeing wildlife. Coveys of
Gambel’s quail explode into the air, peccaries snort through the underbrush,
butterflies festoon flowering shrubs, and coyotes stealthily hunt.

Invertebrates

Insects are generally not bothered by excessive heat, and many species are
active during the hottest hours. This is especially true when the plant
blossoming season is at its height. Flowers of the mesquite, paloverde,
catclaw, saguaro, and other desert plants are “alive” all through the day, as
many species of insects seek nectar and pollen or prey on other insects
attracted to the blossoms. Insects are fed upon by various species of birds;
flycatchers flock to parts of the desert where nectar-yielding flowers are
numerous. Because of the absence of extreme cold, the desert climate
enables insects to be active throughout much of the year and to support a
considerable bird population.

Despite its fearsome appearance and reputation, you have nothing to
fear from the tarantula.

Insects play a far more important role in the plant and animal life of the
desert than is usually realized. Many desert flowers must be insect pollinated
to produce viable seeds. Birds of many kinds depend upon insects for food,
and even the seed-eating birds, during the nesting season, rely upon insects
to provide the enormous quantities of food and moisture required by their
fast-growing nestlings. Many other desert creatures, including certain 63
snakes and lizards and some spiders, depend upon insects for food. The
body juices of the insects provide the all-important moisture—which these
creatures can get from no other source. Bats, too, are insect eaters, spending
the hours of darkness in seemingly aimless and erratic flight while foraging
for moths and other night-flying insects that visit the light-colored blossoms
of night-blooming plants.

Some species of insects may become so numerous that they threaten the very
life of the plants on which they live. Pine bark beetles annually damage or
kill numbers of pinyons and ponderosas in the Rincon Mountains, but have

been kept sufficiently under control by their natural enemies so that their
ravages have not reached epidemic proportions.

Among the common spectacular insects is the TARANTULA HAWK, a large
blue-black, red-winged wasp that preys on large spiders. Temporarily
paralyzing the spider with its sting, the wasp lays a single egg on its victim,
thereby assuring an abundance of living food for its young. The PRAYING
MANTIS is another large insect, usually green and inconspicuous among the
foliage of desert plants, which it frequents in search of small insects. Ants of
many species are active almost everywhere in the desert, harvesting seeds of
various plants. Some species construct mazes of underground nest tunnels
and deposit the excavated materials on the surface, forming conical,
sometimes, craterlike, anthills.

The small desert hairy scorpion is the only scorpion in the monument
that is dangerous to humans.

Along with the insects, other arthropods (jointed-leg creatures with
exoskeletons) find their home in the desert. The arachnids (eight-legged

arthropods) include spiders and scorpions. Of the former, the NORTH 64
AMERICAN TARANTULAS are famous for their large size and formidable
appearance, which have given them the wholly undeserved reputation of
being dangerous to humans. The really dangerous creatures are the
SCORPIONS, whose long, flexible tails bear a poisonous stinger at the tip.
Several species are found in the monument; but only the small, straw-
colored scorpion has venom known to have been fatal to humans. The other
scorpions found in the area can inflict painful stings, but with only localized
and rarely serious effects.

The Colorado River toad is exceeded in size among U.S. toads only by
the giant toad of south Texas (and Mexico).

Amphibians

As might be expected, amphibians are scarce in the monument because of
lack of permanent water. The few springs and seeps, however, furnish
excellent breeding places for several species of amphibians. Best known

among these are the RED-SPOTTED TOAD, LEOPARD FROG, and CANYON
TREEFROG, the latter common near Manning Camp. A spectacular desert
amphibian and the second largest toad in the United States, is the huge
COLORADO RIVER TOAD, sometimes found near residences in the evening
when outdoor lights attract swarms of insects.

Reptiles

Except for small lizards, reptiles are not much in evidence in the monument.
Nevertheless, they are present and are important in the various plant- 65
and-animal communities in which they live. Almost all lizards are
insectivorous, and along with birds and other insect-eaters help to keep the
number of insects within bounds. A notable exception is the GILA (HEE-lah)
MONSTER, (See appendix for scientific names of reptiles) largest of the
lizards found in the United States. (It is one of the world’s two poisonous
lizards, and the only one found in this country.) The gila monster is
especially fond of bird eggs, and also eats nestlings and small rodents,
obtaining necessary moisture from their body juices. These food habits are
quite similar to those of the several species of snakes found in the
monument, the majority of which are perfectly harmless to humans.

The short-horned lizard, more cold-tolerant than the desert horned
lizard, ranges from the foothills into the mountain forests of Saguaro.

Just as the lizards help to control the insect population, the snakes are
important in preventing the buildup of large numbers of rodents that would
result in widespread damage to vegetation. Visitors to the monument rarely
have the opportunity to observe snakes, since they are in hibernation during
winter and remain in the shade or in underground burrows during the hot
part of each summer day. Perhaps those most frequently seen are the GOPHER
SNAKE and the COACHWHIP. Many desert snakes hunt only at night; others
that are normally active during days of moderate temperatures become night
hunters during hot weather. Although they are not abundant, there are several
kinds of rattlesnakes in the monument, the commonest desert species being
the WESTERN DIAMONDBACK and MOHAVE RATTLESNAKES. Except for the 66
small, very rare, and secretive ARIZONA CORAL SNAKE, rattlesnakes are
the only poisonous snakes in the monument. Snakes, like other living things
in the national monument, are protected by law.

Don’t be surprised while following a desert footpath to come upon a
plodding tortoise. This bona fide desert dweller, the DESERT TORTOISE, is a
vegetarian, feeding on cactus, grass, and other low-growing plants.

Birds

Because of its great variety of habitats, ranging from luxurious desert
vegetation to deep mountain forests, Saguaro National Monument provides
food and shelter for many species of birds. Some of these reside all year
within a single zone, while others move upward in summer, returning to the
desert when the mountaintops are covered with snow. Other species pass
through the monument in spring and autumn in their annual migrations
between Latin America and summer nesting grounds in northern United
States or Canada. The following species are those you are most likely to see.

The Mojave rattlesnake prefers desert, grassland, and open brushland to
densely vegetated areas.

A common year-round desert resident is the CURVE-BILLED THRASHER,
noticeable, noisy, and about the size of a robin. These energetic 67
inhabitants of the cactus forests nest in mesquite clumps and cholla
thickets. Their diet—they feed on insects and succulent fruits—makes them
comparatively independent of water. The thrashers are delightful songsters.
The CACTUS WREN, looking somewhat like a small thrasher, is even noisier. It
protects its nest by building in a cactus. This wren lives largely on a diet of
insects, but about 17 percent of its food is seeds and fruits. One of the most
attractive of the ground birds is the GAMBEL’S QUAIL. Many coveys are found
throughout the desert within close range of water. In winter, Gambel’s quail
feed mainly on seeds, berries, and plant shoots; in summer they augment this
diet with ants, grasshoppers, and other insects. The ROADRUNNER, ungainly
clown of the desert, is frequently seen by visitors as it scuttles through the
underbrush along the margins of sandy washes. Not particular as to food, it
is sometimes seen with the tail of a lizard protruding from its beak, and it is
known to eat insects and spiders, snakes, young rodents, small birds, seeds,
and fruits. Quite capable of flight, the roadrunner prefers to trust to its legs
and the security of thickets, but will take to its wings if pursued in the open.

You may mistake the curve-billed thrasher’s call, “whit-wheet,” for a
human whistle of attention.

Two members of the woodpecker family closely associated with the saguaro
cactus are the GILA WOODPECKER and GILDED FLICKER. Called carpenter birds
because they drill nest holes or pockets in the saguaro stems, both 68
species are of particular interest because of their limited range and
specialized habitat. Two other desert birds, sufficiently similar to be
confused, are the red, black-faced CARDINAL and the gray-and-red
PYRRHULOXIA, both of which have crests. Look for these species in the
shrubs along washes. Several kinds of doves are found in the desert,
including the common MOURNING DOVE and the WHITE-WINGED DOVE.
Mourning doves are all-year residents, while the large white-wings drift in
from Mexico in May, remaining long enough to raise families and join other
animals in harvesting fruits of the saguaro.

The gilded flicker drills its nest hole in the saguaro.

Seen and heard in the desert all year, the canary-voiced HOUSE FINCH raises
its family among cholla and mesquite thickets. The tinkling song of the ROCK
WREN is a familiar sound in the desert in winter. These gray ground dwellers
go farther north or to higher elevations to nest.

The PHAINOPEPLA is one of the most noticeable of the desert birds because of
its silky crest, glossy black plumage, and habit of perching on the topmost
branch of a tree while indulging in flutelike song. A permanent resident of
the monument, subsisting on mistletoe berries and other vegetable matter in
winter, it has a diet of insects, principally ants, during the rest of the year.
Flycatchers are especially abundant and conspicuous during spring and 69
early summer when the blossoms of trees, shrubs, and the larger

cactuses attract swarms of insects. Among these birds are SAY’S PHOEBE and
ASH-THROATED FLYCATCHER. The LESSER NIGHTHAWK lives on a diet of insects,
which it catches while on the wing. It is especially noticeable from May to
September as it skims the tops of the tallest saguaros in the dusk of evening.
The lesser nighthawk also ranges up to the oak woodlands.

The white-winged dove’s interest in the saguaro is in the nectar and
fruit.

Predators are an integral part of the bird population, one of the smallest and
most active being the LOGGERHEAD SHRIKE. This black-and-gray bird gorges
itself on beetles and grasshoppers when insects are abundant, turning to
lizards, rodents, and small birds at other times. It has the unusual habit of

impaling its prey on thorns for future use. The RED-TAILED HAWK is the
commonest of the large soaring hawks, which live mainly on rodents and
reptiles. It builds its large stick nest in the forks of saguaro arms. Like the
shrike and the SPARROW HAWK, the red-tailed hawk is found in grasslands,
chaparral, and woodlands as well as in the desert. Because of their nocturnal
habits, owls are not often seen by visitors, but they are abundant in the
monument. In addition to the GREAT HORNED OWL, which like the red-tailed
hawk feeds principally on rodents and builds cumbersome nests in saguaro
branches, the SCREECH OWL and the tiny ELF OWL are numerous in the 70
cactus community. Screech and elf owls make use of abandoned
woodpecker holes in saguaros, not so much for nesting as for dark and
comfortable hiding places during daylight hours; they emerge after sunset to
hunt insects and small rodents. Best known of the carrion eaters, the TURKEY
VULTURE is rarely seen on the ground, but is a common sight, singly or in
groups, circling high in the sky.

The red-tailed hawk builds its nest in the fork of a saguaro and by day
ranges over the entire monument in search of prey.

The oak-pine-juniper woodland has its set of birds too. One of the noisiest,
most quarrelsome, and most mischievous is the MEXICAN JAY, a permanent
resident. In summer, it shares this habitat with the night-flying poor-will,
which closely resembles the nighthawk but lacks the white wing patches.
Shy, secretive, and protectively colored, this bird is rarely seen, but its
plaintive call is a familiar twilight sound at the middle elevations of the
mountains. Here, too, is found the strikingly patterned HARLEQUIN QUAIL,
which waits until you are almost upon it before flushing. The RUFOUS-

SIDED TOWHEE prefers brushy slopes and canyons, where it trills its
monotonous song from the branch of a skunkbush or scratches noisily 71
and industriously among the fallen leaves beneath an oak. And
anywhere from the oak-pine woodland to the top of the Rincons, you are
likely to startle the large BAND-TAILED PIGEON from its perch.

The pine and fir forests of the higher Rincons are rich in bird life in summer,
but only a few species remain the year around. Among the latter is the
STELLER’S JAY, which includes insects in its summer diet but feeds mainly on
acorns and other vegetable material in winter. The MOUNTAIN CHICKADEE is
busy among the branches of the large pines and firs even when snow lies
deep on the ground. PIGMY NUTHATCHES—tiny, constantly twittering insect-
eaters—also remain all year.

The great horned owl, a nocturnal counterpart of the red-tailed hawk,
nests in the saguaro and feeds primarily on rodents.

Steller’s jay lives year-round in the pine and fir forests of the higher
Rincons.

In summer, when insects are plentiful, the mountain forests are alive with
birds. The MEXICAN JUNCO, which winters at lower elevations, hides its nest
in grass clumps among the firs and aspens. Hummingbirds of several species
pause on vibrating wings to suck nectar from blossoms in the meadow at
Manning Camp. Brightly colored summer visitors such as the HEPATIC 72
TANAGER and the PAINTED REDSTART search for insects among the pine
boughs or flash in the sunlight as they flutter across open glades in the

forest. The mountaintops, too, have their predators; the COOPER’S HAWK,
which nests in wooded canyons, is large enough to lift a pigeon or rabbit, but
generally preys on rodents and smaller birds. The largest bird known to
inhabit the Rincon Mountains is the TURKEY, which nests and raises its
young among the firs and aspens. It descends in winter to the oak-pine
woodlands, where it feeds on pinyon nuts, acorns, and grass seeds.

Mammals

The most frequently seen mammals in the monument are rodents and
members of the hare clan. Among the latter group are two rabbits. The
DESERT COTTONTAIL is common in the lower levels of the desert, and the
EASTERN COTTONTAIL inhabits the mountains to 8,600 feet. Adaptable to a
wide range of environmental conditions, these animals augment the water
they obtain from springs with moisture derived from sap. There are two
species of JACKRABBITS (actually hares) in the monument. They remain at the
lower levels, where they are a common sight amid the cactuses. Unlike
rabbits, which are born naked, blind, and helpless, hares are born with fur,
open eyes, and the ability to move about.

The Yuma (or gray-tailed) antelope ground squirrel, a chipmunk-like
rodent of the desert and grassland.

In the monument, the cliff chipmunk prefers the oak-pine woodland and
the coniferous forest.

Among the monument rodents the largest are the PORCUPINES. Though 73
rarely seen, they leave characteristic scars on pinyons and ponderosa
pines, recording their feeding habits at higher elevations. They are also
active in the chaparral belt, and an individual occasionally wanders down
into the desert where it eats mesquite beans and samples the bark of ocotillos
and other shrubs and trees.

Several species of ground squirrels are abundant. At the lower levels,
especially among creosotebushes, the ROUNDTAIL GROUND SQUIRREL finds
suitable living conditions, while the YUMA ANTELOPE GROUND SQUIRREL
ranges from the cactus forests into grassland. At this elevation and upward
through the pinyons and junipers, the ROCK SQUIRREL makes its burrows in

rocky ledges and brushy canyons. CLIFF CHIPMUNKS enliven the oak-pine
woodland and higher forests with their quick movements and cheerful
chatter.

KANGAROO RATS honeycomb the soil from the cactus forests up to the oak-
pine belt. Remaining underground during the day, they are frequently seen at
night. These animals do not require free water; they obtain adequate
moisture from a chemical process within the body during the digestion of
food, which is mostly dry seeds. WOODRATS, famous in song and story as
pack rats or trade rats because of their habit of carrying away objects of
human use and leaving something else in their place, are found throughout
the monument at all elevations. Look for their stick nests among the pads of
prickly pear, a favorite food.

Other rodents common in the monument include the CACTUS MOUSE,
GRASSHOPPER MOUSE, DEER MOUSE, and VALLEY POCKET GOPHER.

The four species of kangaroo rats found in Saguaro look too much alike
to be distinguished in the field.

74

Mule deer.

Among the larger mammals in the monument are two species of deer. The
MULE DEER subsists in winter on cactus fruits, ephemerals, and other desert
vegetation. In summer they find abundant browse in the higher oak
woodland. The forested areas along the crest of the Rincons support a
population of the smaller WHITETAIL DEER. These graceful animals browse on
aspen, buckbrush, and other shrubs and small trees. They are particularly
fond of acorns. When snow flies some descend to the protective cover of the
oak-pine woodlands and chaparral.

PECCARIES, characteristic of southwestern deserts, usually travel in herds of
from three to as many as 50 animals. They wander through the groves of
mesquite along desert washes, and root among beds of pricklypear.
Pricklypear pads are their chief food; they are said to feed upon cactus fruits
in summer and autumn. In addition to the moisture obtained from succulent
stems and fruits, peccaries require considerable water, hence they frequent
springs and seeps. Small bands of these animals occasionally visit the

waterhole near the visitor center, where they are excitedly watched by
visitors fortunate enough to be in the lobby at the time.

Saguaro National Monument also has a large number of predatory animals.
Many of these, popularly believed to be exclusively meat-eaters, actually
also eat much vegetable matter. The predators—an exciting part of the
monument’s fauna—play an important role in preventing overpopulation of
the prolific rodents.

Chief among predators is the COYOTE, which ranges throughout the
monument. In winter, coyotes are found principally below 6,000 feet, 75
where hunting is easier and where rodents remain longer out of
hibernation. They are also known to roam the forested heights of the
Rincons and Tanque Verde Ridge. Studies of coyotes in the monument made
by biologist Lowell Sumner in January 1951 showed that their winter diet
consisted of about 78 percent fruits and seeds, 11 percent small rodents, 7
percent deer, 4 percent birds, reptiles, insects, and carrion, and 1 percent
debris. The coyote is one of the principal wild creatures associated with the
history of the West, and its continuing presence in the monument brings a
thrill of pleasure to visitors who hear the voices of the pack during the calm
of evening, or catch a glimpse of one of these gray canines trotting through
open stands of saguaros. BOBCATS, ranging over much the same territory as
coyotes, subsist principally on rodents, birds, and insects. Because of their
secretive habits, they are seldom seen.

Collared peccary, or javelina.

The GRAY FOX is another fairly common inhabitant of the cactus desert and
higher brushlands, and is also known to roam the forested uplands. It is
usually seen at night. Rodents are its principal source of food, but it also
preys on birds and reptiles and eats much vegetable matter. The smaller and
rather rare KIT FOX, restricted mostly to the desert, is also a night hunter.
Kangaroo rats are a favorite item in the kit fox diet, but these small predators
also eat grasshoppers and other insects.

Skunks, members of the weasel family, are relatively common in the
monument, and several species inhabit areas where water is available. They
are usually active at night. The HOGNOSE SKUNK is a desert dweller
recognizable by its solid-white back. It roots for insect larvae and eats 76
cactus fruits, bird eggs, and nestlings. The STRIPED SKUNK ranges
throughout the monument; the SPOTTED SKUNK is found at all elevations,
usually among rocks. Insects, rodents, and fruits are its main food.

Another member of the weasel family, the BADGER, is occasionally seen in
the desert although it is by no means limited to that habitat. The badger feeds
mainly on rodents, which it digs from burrows with its strong forelegs and
heavy claws.

The RACCOON, longer-legged than the badger, is readily recognized by its
gray fur, black mask, and ambling gait. It inhabits brushy canyons having
permanent water, and sometimes wanders up into the pine belt in summer.
Amphibians, scarce as they are, and other water creatures are among the
preferred foods of raccoons; but they also eat small rodents and plant food,
including berries, acorns, and other fruits.

Badger.

The RINGTAIL, a smaller relative of the raccoon, is somewhat similar in
habitat preference and nocturnal habits. Its flattened, bushy tail, acting as a
balancer, helps this short-legged, agile animal in leaping from point to point

on the steep rocky surfaces it seems to favor. It sometimes takes up residence
in little-used or abandoned buildings, where small rodents, its principal 77
source of food, are usually abundant. About the size of a house cat, it
has large eyes and ears and alternating dark and light bands on its tail.

A tropical animal that seems to be extending its range northward, the COATI
(or coatimundi) is often seen in the forests of the Rincons. With long snout
and long, banded tail, it looks something like an elongated raccoon, to which
it too is related. These omnivorous animals travel in bands, rooting among
leaves for insects and whatever else they can find.

Coati, or coatimundi.

78

Desert vegetation near Red Hill, Tucson Mountain Section.

79

the rhythms of nature
Natural landscapes may appear unchanging, but this is illusion. Within the
apparent constancy, daily and seasonal cycles, fluctuations in numbers, and
long-term change are the rule.

Daily cycles are obvious to those who are about at the edges of the day. Take
24 summer hours in the cactus forest of Saguaro National Monument. When
the first light comes over the mountains, curve-billed thrashers and cactus
wrens sing noisily among the chollas. Other birds soon join in. The early
morning walker is likely to hear peccaries grunting in the mesquites along a
wash, or see mule deer staring at him, frozen like statues before sudden
flight to a sheltering thicket.

At midday, the scene is quiet. Nothing stirs under the baking sun except
perhaps a vulture, soaring on the hot air currents. The desert creatures have
not gone—they are in the shade of bushes or underground. Even some of the
plants are “taking a siesta,” having folded their leaves or closed their leaf
pores.

Soon after sundown the desert comes to life again. The birds give a subdued
version of their morning’s vocal performance. Tarantulas begin their slow,
stately walk over the ground searching for prey or mates. Coyotes stretch
and howl—a prelude to the evening’s hunt. As night falls, rattlesnakes
emerge from their cool retreats to search out kangaroo rats, which in great
numbers are scrutinizing the sand for seeds. And through the night, creatures
of many other kinds hunt food to last them through another broiling day.

The rhythmic patterns of the daily cycle are paralleled on a larger scale
through the year—seasons of activity follow seasons of quiet. In the desert,

rain or lack of rain marks the changes, though gradually rising or falling
temperature adds its impact.

The gentle rains of winter prepare the way for the year’s greatest burst of
activity. By March, spring flowers are blooming and birds are starting to
nest. Snakes begin to come out of hibernation. April and May see the apex of
spring activity, as insects swarm around the flowering plants, and birds take
advantage of this proliferation of food to raise their young. The desert now is
yellow with the blossoms of paloverde, mesquite, acacia, and 80
brittlebush.

But April also marks the beginning of a drought that intensifies through May
and June, making these last 2 months the year’s parching crucible in which
reproductive ability is tested. If winter rains have been meager, the heat and
drought of May and June can kill all the young of many birds. Some birds,
such as Gambel’s quail, may not even attempt to nest in a dry year.
Conditions may be so harsh at this season that some mammals, such as the
pocket mouse, close up shop completely, sleeping the days away
underground.

Relief comes with the rains of July and August. Now the summer annuals
spring magically from the ground, perennials put forth new leaves, and
saguaros do all their growing for the year. This summer burst of plant growth
is accompanied by a new hatching of insects, which allows a few more birds
to nest, and along with the new vegetation supports a larger pyramid of
animal life generally. Among the new animals that reappear are toads, which
now emerge from their long sleep in the soil to mate and lay eggs in the
pools formed by summer rains.

When the last torrential rain of August or September falls, a new dip in the
yearly cycle of activity begins. This one is not so deep, not so trying, as the
drought of early summer, but it too is a time of relative quiet. Roundtail
squirrels go underground to sleep until cooler weather comes. Now the
migrating birds slip through, hardly noticed among the mesquites and
paloverdes. Butterflies lay their eggs, in preparation for a new generation
beyond the winter. Signaling the last phase in the yearly cycle, wet canyons
turn yellow and brown as cottonwoods, willows, and sycamores present a
pale version of the spectacular foliage displays seen in the East.

While these daily and seasonal cycles are following their well-known
courses, each species of plant and animal is undergoing its own fluctuations,
in a constant struggle that generally goes unnoticed. For the balance of
nature is not a static one, but more like the rocking of a seesaw on its
fulcrum. The population of a species goes up one year, down another—
depending on the weather, the food supply, predators, competitors, and a
thousand interactions that reverberate through the community in which it
lives. The numbers of some species, like the Gambel’s quail, fluctuate wildly
from year to year, while those of others, such as the harvester ant, remain
quite stable. But the oscillations of the seesaw, big and little, average out
from year to year so that the species maintains itself in the community. The
other members are going through the same thing, in a system of checks and
balances that over the short run keeps the whole community nearly 81
constant.

But over decades, centuries, or longer, the fulcrum of the seesaw moves: the
larger environment changes, and the community and its constituent plants
and animals must change with it or perish. Such changes may be climatic, as
we saw with the formation of the Southwestern deserts; or it may be
geologic, as with the rising and partial disintegration of the Rincon
Mountains. The efforts of plant and animal species to meet such changes
constitute in large part the story of evolution, for new environments spawn
newly evolved forms of life. Evidence of such evolution we have seen in the
plants of the Sonoran Desert, notably the giant saguaro cactus, whose prickly
ancestor lived in the West Indies only 20,000 years ago.

Thus nature is ever-changing; and the inexorable rule for all living things is,
“adapt or perish.” Before technological man enters the scene, the slow
evolutionary process can keep pace with the changing environments, though
here and there a species is dropped by the wayside. Generally, communities
of living things reach new equilibria without serious disruption.

But what happens when man, with his machines and his passion for
progress, institutes changes of a speed and kind and on a scale drastically
different from those brought about by earthquakes, storms, shifting climates,
and other natural phenomena? What happens to the living things that have
adapted to the harsh desert environment when that environment is drastically
altered?

82

83

the impact of man
Man has been a part of the scene in this region for several thousand years,
but until recent times his influence on it was minimal. Only with the rapid
technological development of the last century has man been able to make a
major impact on this landscape. Thus the story of man, here as elsewhere, is
a story of gradually accelerating power to change environments, a power that
now threatens to destroy environments, and with them, man himself.

From carbon-14 dating in Ventana Cave, we know that man was here at least
12,500 years ago, in the Pleistocene age, a time that was cool and moist
compared to the present. Living by hunting, he followed mammoths and
other large mammals. As the climate warmed during succeeding
millenniums, and these mammals became extinct, he came to rely more on
plant foods. These hunters and gatherers necessarily had to live in small
bands scattered over the land, since the plants and animals on which they
depended were widely dispersed. By 300 B.C., they had learned from people
to the south how to cultivate food plants, and had developed a sedentary way
of life. About 2,300 years ago a group we call the Hohokam settled in the
Salt and Gila River basins (including the Santa Cruz Valley). By A.D. 700
they had a well developed agricultural economy including extensive
irrigation systems. Pottery fragments, projectile points, petroglyphs (rock
carvings), and other evidence show that Hohokam villages existed for about
600 years in the eastern section of the monument along Rincon Creek and its
tributary washes. Archeological work in the Tucson Mountain Section has
indicated that this area was visited only temporarily by the Hohokam, for
hunting, food gathering, and perhaps ceremonial purposes.

During the 15th century the Hohokam high culture vanished. Soils made
salty from irrigation water and internecine warfare are suggested

explanations.

When the Spanish explorer Coronado passed to the east of the Rincons in
1540, he found the Sobaipuri living there. The Pimas, descendants of the
Hohokam, occupied the same basins the Hohokam had. To the west, in drier
country, lived the Papago. These tribes, thought to be descendants of the
Hohokam, lived much the same sort of life, practicing irrigation where
surface water was available, hunting and gathering where it was not.

The period of Spanish rule, implemented by a series of missions, began 84
in the Santa Cruz Valley about 1692, when the energetic Father Kino
began his work among the Pima and Papago. The mission system
concentrated the Indians in fewer places, brought Spanish and, later,
Mexican settlers into southern Arizona, and introduced sheep, cattle, and
goats. Although the new culture must have had some environmental effects,
there is no evidence of drastic change. Grass was plentiful, and streams,
including the Santa Cruz, remained marshy and unchanneled.

After the Gadsden Purchase of 1853-54, however, when the present
boundary with Mexico was established and this area came into United States
ownership, man’s impact on the land increased. Apache raiding had been a
deterrent to settlement during the 18th and 19th centuries, but, after the Civil
War, American soldiers got the upper hand and settlement increased.
Following completion of the Southern Pacific Railroad to Tucson in 1879, a
cattle boom began. The disastrous results of the livestock explosion of the
eighties—overgrazing, soil erosion, and starvation of cattle—we have
already seen in the story of the saguaro cactus. In 1890, a flood cut a deep
channel in the Santa Cruz River, transforming it from a meandering, marshy
stream to the usually dry incision one sees today. The arroyo cutting of this
and many other rivers throughout the Southwest was undoubtedly due partly
to increasing aridity, which reduced the plant cover and its water-holding
capacity. But the erosion was probably triggered by overgrazing.

In the monument, we have already seen how grazing pressure, hunting, and
predator control reduced ground cover and led to an upsurge of certain
rodents and a decline in large mammals. But there have been other man-
induced changes. For as long as there has been forest on top of the Rincons,
there has been fire. Lightning-caused fire is a natural part of ponderosa-pine

forest, every few years burning the litter and small trees and shrubs from the
forest floor, and thus maintaining open stands of tall trees. But since 1908,
when the Rincon Mountains came under protection of the Forest Service,
U.S. Department of Agriculture (to be followed in 1933 by National Park
Service, U.S. Department of the Interior protection), fires have been put out
as fast as possible. This policy has resulted in a paradox. On the one hand,
thickets of scrawny young pines and shrubs such as buckbrush have
developed in many places under the tall pines. On the other hand, the
accumulation of litter and low-level vegetation has provided fuel over the
years for occasional very hot crown fires, which have been hard to control
and which have burned large acreages. On top of the Rincons you can see
several meadows that resulted from these fires. Only a few scattered trees
and stumps remain in them to suggest the forest that once was there.

Ideally, national parks and monuments should be “vignettes of 85
primitive America”—naturally evolved landscapes in much the same
condition as when first seen by Europeans. In reality they are compromises
—beautiful, wild, but still bearing the marks of human occupation. In
Saguaro, as we have seen, fire control has produced a forest different from
that known to the Indians who once lived here; grazing has depleted the
ground cover; and hunting has removed the desert bighorn from its rocky
haunts. In these days of burgeoning population, when human influence is
affecting every natural landscape, environmental management becomes
necessary to approach the ideal of naturalness. This may mean “prescribed
burns” to return forests to their earlier state; elimination of grazing; or
reintroduction of animals once native to a park. In the summer of 1971, after
2 inches of rainfall, natural burns (caused by lightning strikes) were allowed
to run their courses.

Some or all of these measures may be taken in Saguaro, in order that future
generations will know a piece of the Sonoran Desert as it was in Coronado’s
time.

The realization of this goal, however diligently we work toward it, seems
almost each day to become more difficult of attainment. These desert and
mountain environments—which once seemed secure, needing only the
continued protection afforded by their status as a national monument—are
increasingly imperiled by the works of man. As the city of Tucson sprawls in

all directions, the monument’s two divisions, islands in an encroaching sea
of civilization, must withstand ever-accelerating hazards. Vandalism takes an
increasing toll of the saguaros; housing developments creep toward the
monument borders. Smog drifts over the fragile plant communities,
threatening to choke them—as the polluted air from Los Angeles is already
strangling forests in the distant San Bernardino Mountains.

A new awareness that the best-managed preserve cannot thrive
independently of what is happening in the surrounding region only
emphasizes the difficulty of the task. Saving the saguaros is inevitably tied
to the problem of enhancing the quality of life and reversing the degradation
of the environment—not only in Tucson but throughout the Southwest.

There is no time to waste. Only concerted effort by scientists, resource
managers, and the community can assure that our grandchildren will be able
to visit a Saguaro National Monument where coyotes howl under the moon,
peccaries snort through the washes, and giant cactuses lift bristly green arms
into a blue sky.

87

appendix

Suggested Reading

Arnberger, Leslie P. Flowers of the Southwest Mountains. Southwestern
Monuments Association, Popular Series No. 7. Globe, Ariz. 1962.

Benson, Lyman D. The Cacti of Arizona. University of Arizona Press,
Tucson. 1969.

Burns, William A. (ed.). The Natural History of the Southwest. Franklin
Watts, Inc., New York. 1960.

Dodge, Natt N. Flowers of the Southwest Deserts. Southwestern Monuments
Association. Popular Series No. 4. Globe, Ariz. 1961.

——. Poisonous Dwellers of the Desert. Southwestern Monuments
Association. Popular Series No. 3. Globe, Ariz. 1964.

Dodge, Natt N., and Herbert S. Zim. The Southwest. Golden Press, New
York. 1962.

Earle, W. Hubert. Cacti of the Southwest. Desert Botanical Garden. Phoenix,
Ariz. 1963.

Jaeger, Edmund C. The North American Deserts. Stanford University Press,
Stanford, Calif. 1957.

Kearney, Thomas H., Robert H. Peebles, and collaborators. Arizona Flora.
University of California Press, Berkeley. 1960.

Krutch, Joseph W. The Voice of the Desert. William Sloane Associates, Inc.,
New York. 1955.

Milne, Lorus, and Margery Milne. The Balance of Nature. Alfred A. Knopf,
Inc., New York. 1960.

Olin, George. Mammals of the Southwest Deserts. Southwestern Monuments
Association, Popular Series No. 8. Globe, Ariz. 1965.

——. Mammals of the Southwest Mountains and Mesas. Southwestern
Monuments Association, Popular Series No. 9. Globe, Ariz. 1961.

Patraw, Pauline M. Flowers of the Southwest Mesas. Southwestern 88
Monuments Association. Popular Series No. 5. Globe, Ariz. 1959.

Phillips, Allen, Joe Marshall, and Gale Monson. The Birds of Arizona.
University of Arizona Press, Tucson. 1964.

Schmidt-Nielsen, Knut. Desert Animals: Physiological Problems of Heat
and Water. Oxford University Press, Inc., New York. 1964.

Sears, Paul B. Deserts on the March. University of Oklahoma Press,
Norman. 1959.

Stebbins, Robert C. Amphibians and Reptiles of Western North America.
McGraw-Hill Book Co., New York. 1954.

Storer, John H. The Web of Life. The Devin-Adair Co., Old Greenwich,
Conn. 1960.

Sutton, Ann, and Myron Sutton. The Life of the Desert. McGraw-Hill Book
Co., New York. 1966.

Underhill, Ruth. People of the Crimson Evening. Publications Service,
Haskell Institute, Lawrence, Kans. 1951.

89

Common and Scientific Names of Plants

Agave—See Amole
Alligator juniper—Juniperus deppeana
Amole—Agave schottii
Arizona cypress—Cupressus arizonica
Arizona rosewood—Vauquelinia californica
Arizona sycamore—Platanus wrightii
Arizona white oak—Quercus arizonica
Aster—Aster commutatus

Barrel cactus—Ferocactus wislizenii, F. lecontii
Beargrass—Nolina microcarpa
Bladder-pod—Lesquerella gordoni
Bluedicks—Dichelostemma pulchellum
Blue paloverde—Cercidium floridium
Bluegrass—Poa fendleriana
Boxelder—Acer negundo
Bracken—Pteridium aquilinum
Brittlebush—Encelia farinosa
Buckbrush—Ceanothus fendleri
Bullgrass—Muhlenbergia emersleyi

Catclaw—Acacia greggii
Chain fruit cholla—Opuntia fulgida
Chihuahua pine—Pinus chihuahuana
Chokecherry—Prunus virginiana
Cinquefoil—Potentilla subviscosa
Cologania—Cologania lemmoni
Creosotebush—Larrea tridentata
Curly mesquitegrass—Hilaria belangeri

Desert chicory—Rafinesquia neomexicana
Desert Christmas cactus—Opuntia leptocaulis
Desert-marigold—Baileya multiradiata
Dogbane—Apocynum androsaemifolium
Douglas-fir—Pseudotsuga menziesii

Emory oak—Quercus emoryi

Fairy-duster—Calliandra eriophylla
Fiddleneck—Amsinckia intermedia
Filaree—Erodium cicutarium
Fishhook cactus—Mammillaria sp.
90

Fleabane—Erigeron arizonicus

Gambel’s oak—Quercus gambelii
Goldenrod—Solidago sparsiflora
Goldfern—Pityrogramma triangularis
Gourd—Cucurbita digitata
Grama—Bouteloua sp.
Groundsel—Senecio neomexicanus

Hairy grama—Bouteloua hirsuta
Hedgehog cactus—Echinocereus sp.
Houstonia—Houstonia wrightii

Indian wheat—Plantago purschii
Indigobush—Dalea sp.
Ironwood—Olneya tesota

Jointfir—Ephedra sp.
Jojoba—Simmondsia chinensis

Lupine—Lupinus sp.

Marigold—Tagetes lemmoni
Mesquite—Prosopis juliflora
Mexican blue oak—Quercus oblongifolia
Mexican pinyon pine—Pinus cembroides
Mexican white pine—Pinus strobiforms
Mock-pennyroyal—Hedeoma hyssopifolium
Mountain-mahogany—Cercocarpus breviflorus
Mountain muhly—Muhlenbergia montana

Netleaf hackberry—Celtis reticulata
New Mexican alder—Alnus oblongifolia

New Mexican locust—Robinia neomexicana
Nightblooming cereus—Peniocereus greggii

Ocotillo—Fouquieria splendens
Orange sneezeweed—Helenium hoopesii

Palmer oak—Quercus palmeri
Paper flower—Psilostrophe cooperi
Parry’s penstemon—Penstemon parryi
Peavine—Lathyrus graminifolius
Pencil cholla—Opuntia arbuscula
Phacelia—Phacelia crenulata
Pincushion cactus—Mammillaria sp.
Pine dropseed—Blepharoneuron tricholepis
91

Pointleaf manzanita—Arctostaphylos pungens
Ponderosa pine—Pinus ponderosa
Pricklypear—Opuntina engelmannii and others
Puccoon—Lithospermum multiflorum

Quaking aspen—Populus tremuloides

Sacahuista—See Beargrass
Saguaro—Carnegiea gigantea
Scorpionweed—Phacelia crenulata
Screwleaf muhly—Muhlenbergia virescens
Shindagger—See Amole
Shrub live oak—Quercus turbinella
Sideoats grama—Bouteloua curtipendula
Silktassel—Garrya wrightii
Silverleaf oak—Quercus hypoleucoides
Skunkbush—Rhus trilobata
Snakeweed—Futierrezia sp.
Snowberry—Symphoricarpos oreophilus
Sotol—Dasylirion wheeleri
Spanish dagger—Yucca schottii
Sprucetop grama—Bouteloua chondrosioides

Staghorn cholla—Opuntia versicolor

Tanglehead—Heteropogon contortus
Teddy bear cholla—Opuntia bigelovii
Texas bluestem—Andropogon cirratus
Triangle bursage—Franseria deltoidea
Turpentine-bush—Haplopappus laricifolius

Vine mesquite grass—Panicum bulbosum

Western yarrow—Achillea lanulosa
White fir—Abies concolor
White tackstem—Calycoseris wrightii
Wild carrot—Daucus pusillus
Wild-cucumber—Marah gilensis
Wild-heliotrope—Heliotropium curassavicum
Willow—Salix sp.
Wolfberry—Lycium sp.
Wolftail—Lycurus phleoides

Yellow paloverde—Cercidium microphyllum

92

Reptiles and Amphibians of the monument.

This checklist names reptiles and amphibians that have been seen, or that
should occur, according to range maps and distribution records in important
reference works, in the monument. Four of these species are found only in
the Tucson Mountain Section; they are: desert iguana, desert horned lizard,
western shovel-nosed snake, and sidewinder. An asterisk marks those species
most commonly seen in the daytime.

The desert (D) habitat is the rather flat or gently rolling terrain below 3,200
feet in elevation, as seen in the vicinity of the visitor center and the Cactus
Forest Drive, and in the north and west portions of the Tucson Mountain
Section.

The foothills (F) habitat includes the area above 3,200 feet where the land
becomes quite rocky and begins to ascend rather sharply on the Cactus
Forest Drive and along Hohokam Road in the Tucson Mountain Section.

The mountain (M) habitat is restricted to the Rincon Mountains above an
elevation of 6,500 feet where one finds tall trees.

common name scientific name habitat
AMPHIBIANS toads and frogs
Colorado River Toad Bufo alvarius DF
Great Plains Toad Bufo cognatus D
Red-spotted Toad Bufo punctatus DF
Woodhouse’s Toad Bufo woodhousei DFM
Couch’s Spadefoot Scaphiopus couchi DF
Western Spadefoot Scaphiopus hammondi DFM
Canyon Treefrog Hyla arenicolor FM
Leopard Frog Rana pipiens DFM
REPTILES turtles
*Desert Tortoise Gopherus agassizi DF
Western Box Turtle Terrapene ornata DF
Sonora Mud Turtle Kinosternon sonoriense D F M
Spiny Softshell Trionyx ferox D
lizards
Banded Gecko Coleonyx variegatus DF
Desert Iguana Dipsosaurus dorsalis D
Lesser Earless Lizard Holbrookia maculata DF
Greater Earless Lizard Holbrookia texana DF
*Zebra-tailed Lizard Callisaurus draconoides D F
*Collared Lizard Crotaphytus collaris DF
Leopard Lizard Crotaphytus wislizenii D F
Short-horned Lizard Phrynosoma douglassi FM
Desert Horned Lizard Phrynosoma platyrhinos D
*Regal Horned Lizard Phrynosoma solare DF

*Side-blotched Lizard Uta stansburiana DF
*Tree Lizard Uta ornata DFM
*Desert Spiny Lizard Sceloporus magister DF
Clark’s Spiny Lizard Sceloporus clarki DFM
Eastern Fence Lizard Sceloporus undulatus FM
*Western Whiptail Cnemidophorus tigris DF
Spotted Whiptail Cnemidophorus sacki DF
Arizona Alligator Lizard Gerrhonotus kingi M
*Great Plains Skink Eumeces obsoletus DF
*Gila Monster Heloderma suspectum DF
snakes
Western Blind Snake Leptotyphlops humilis DF
Arizona Coral Snake Micruroides DFM
euryxanthus
Regal Ringnecked Snake Diadophis regalis FM
Western Hognose Snake Heterodon nasicus DF
Spotted Leaf-nosed Snake Phyllorhynchus DF
decurtatus
Saddled Leaf-nosed Snake Phyllorhynchus browni DF
Coachwhip Masticophis flagellum DF
Sonora Whipsnake Masticophis bilineatus DFM
Western Patch-nosed Snake Salvadora hexalepis DF
Mountain Patch-nosed Snake Salvadora grahamiae M
Glossy Snake Arizona elegans DF
Gopher Snake Pituophis catenifer DFM
Compton Kingsnake Lampropeltis getulus DF
Sonora Mountain Kingsnake Lampropeltis M
pyromelana
Long-nosed Snake Rhinocheilus lecontei DF
Black-necked Garter Snake Thamnophis cyrtopsis FM
Mexican Garter Snake Thamnophis eques D
Checkered Garter Snake Thamnophis marcianus DF

Western Ground Snake Sonora semiannulata DF
Western Shovel-nosed Snake Chionactis occipitalis D
Banded Sand Snake Chilomeniscus cinctus DF
Mexican Black-headed Snake Tantilla atriceps DF
Plains Black-headed Snake Tantilla nigriceps DF
Sonora Lyre Snake Trimorphodon lambda DF
Night Snake Hypsiglena torquata DFM
Western Diamondback Crotalus atrox DF
Rattlesnake
Sidewinder Crotalus cerastes D
Black-tailed Rattlesnake Crotalus molossus FM
Tiger Rattlesnake Crotalus tigris F
Mohave Rattlesnake Crotalus scutulatus DF
Arizona Black Rattlesnake Crotalus viridis FM
cerberus
94

Birds of the monument

This checklist is based entirely on written records of observations of birds
seen in the monument. Names are in accordance with A.O.U. Checklist of
North American Birds, 5th edition, 1957. (See checklist of reptiles and
amphibians for description of habitats.)

key to symbols:
D desert habitat
F foothill habitat
M mountain habitat
* species most often seen at lower elevations
s summer resident
w winter visitor
p permanent resident
t transient visitor

occurrence common name

D t White-faced Ibis
D F M s Turkey Vulture
D p Black Vulture
D w Sharp-shinned Hawk
D F M p Cooper’s Hawk
D F M p *Red-tailed Hawk
D F s Swainson’s Hawk
F M s Zone-tailed Hawk
M t Ferruginous Hawk
D F s Harris’ Hawk
D s Black Hawk
F M p Golden Eagle
D w Marsh Hawk
D t Osprey
F M p Prairie Falcon
M p Peregrine Falcon
D F p *Sparrow Hawk
F p Scaled Quail
D p *Gambel’s Quail
F M p Harlequin Quail
M p Turkey
D p Killdeer
D F M t Spotted Sandpiper
D t California Gull
F M s Band-tailed Pigeon
D p Rock Dove
D F s *White-winged Dove
D p *Mourning Dove
D p Ground Dove
D p Inca Dove
D F p Roadrunner

D F M p Screech Owl
M p Whiskered Owl
M p Flammulated Owl
D F M p Great Horned Owl
D s Elf Owl
M p Spotted Owl
M s Whip-poor-will
D F p Poor-will
D F s Lesser Nighthawk
D t Vaux’s Swift
D F M s White-throated Swift
D F M s Black-chinned Hummingbird
D F s Costa’s Hummingbird
D w Anna’s Hummingbird
M s Broad-tailed Hummingbird
M s Rufous Hummingbird
M s Rivoli’s Hummingbird
M s Blue-throated Hummingbird
D F t Broad-billed Hummingbird
M p Red-shafted Flicker
D F p *Gilded Flicker
D p *Gila Woodpecker
F M p Acorn Woodpecker
D F w Yellow-bellied Sapsucker
F M t Williamson’s Sapsucker
M p Hairy Woodpecker
D F p Ladder-backed Woodpecker
F M p Arizona Woodpecker
D s Western Kingbird
D F s Cassin’s Kingbird
D F s Wied’s Crested Flycatcher
D s *Ash-throated Flycatcher

M s Olivaceous Flycatcher
D p Black Phoebe
D p *Say’s Phoebe
M s Western Flycatcher
M s Buff-breasted Flycatcher
M s Coues’ Flycatcher
M s Western Wood Pewee
D F M t Olive-sided Flycatcher
D s Vermilion Flycatcher
M s Violet-green Swallow
D t Barn Swallow
D t Cliff Swallow
D s *Purple Martin
M p Steller’s Jay
F M p Scrub Jay
F M p Mexican Jay
M p Common Raven
D F M p White-necked Raven
M t Clark’s Nutcracker
M p Mountain Chickadee
F M p Bridled Titmouse
D p *Verdin
M p Common Bushtit
M p White-breasted Nuthatch
F t Red-breasted Nuthatch
M p Pigmy Nuthatch
M p Brown Creeper
M p House Wren
F M p Bewick’s Wren
D p *Cactus Wren
D F M p Canyon Wren

D F M p Rock Wren
D p Mockingbird
D t Bendire’s Thrasher
D p *Curve-billed Thrasher
D F p Crissal Thrasher
M p Robin
F M p Hermit Thrush
F M p Western Bluebird
D F M w Mountain Bluebird
F w Townsend’s Solitaire
F M p Blue-gray Gnatcatcher
D p Black-tailed Gnatcatcher
D w *Ruby-crowned Kinglet
D F p *Phainopepla
D F p *Loggerhead Shrike
D p Starling
M s Hutton’s Vireo
D s Bell’s Vireo
M s Solitary Vireo
M s Warbling Vireo
M t Orange-crowned Warbler
M t Nashville Warbler
M s Virginia’s Warbler
D s Lucy’s Warbler
M s Olive Warbler
D t Yellow Warbler
M s *Audubon’s Warbler
M s Black-throated Gray Warbler
F M t Townsend’s Warbler
M t Hermit Warbler
M s Grace’s Warbler

D t MacGillivray’s Warbler
D t Yellowthroat
D t Yellow-breasted Chat
M s Red-faced Warbler
D F M t *Wilson’s Warbler
M s Painted Redstart
D p House Sparrow
D t Meadowlark sp.
D s *Hooded Oriole
D F s Scott’s Oriole
D s Bullock’s Oriole
D w Brewer’s Blackbird
D F s Brown-headed Cowbird
D s Bronzed Cowbird
D F s Western Tanager
M s Hepatic Tanager
D p Cardinal
D p Pyrrhuloxia
M s Black-headed Grosbeak
D w Lazuli Bunting
M p Evening Grosbeak
M t Cassin’s Finch
D F p *House Finch
F M p Pine Siskin
D F M p Lesser Goldfinch
D w Lawrence’s Goldfinch
M p Red Crossbill
D F w Green-tailed Towhee
F M p Rufous-sided Towhee
D p *Brown Towhee
D t Lark Bunting

D F w Savannah Sparrow
D w Vesper Sparrow
D t Lark Sparrow
D F p Rufous-winged Sparrow
F p Rufous-crowned Sparrow
D F p *Black-throated Sparrow
F w Oregon Junco
F w Gray-headed Junco
M p Mexican Junco
F w Clay-colored Sparrow
F w Chipping Sparrow
D F w Brewer’s Sparrow
F p Black-chinned Sparrow
D w White-crowned Sparrow
D F w Fox Sparrow
D F w Lincoln’s Sparrow
97

Mammals of the monument

This checklist names mammals that have been observed, and those that,
mainly according to collection records and distribution maps in The Recent
Mammals of Arizona, by E. Lendell Cockrum, 1960, may occur in the
monument. One species, the desert kangaroo rat, probably occurs only in the
Tucson Mountain Section. (See checklist of reptiles and amphibians for
description of habitats.)

key to symbols:
D desert habitat
F foothill habitat
M mountain habitat
* species most often seen by visitors

habitat common name

M Vagrant Shrew
DF Gray Shrew
DF Leafnose Bat
DF Hognose Bat
DF Longnose Bat
DF Yuma Myotis
DF Cave Myotis
M Long-eared Myotis
F M Fringed Myotis
F M Long-legged Myotis
D F M California Myotis
F M Small-footed Myotis
F M Silver-haired Bat
D F M Western Pipistrel
D F M Big Brown Bat
DF Red Bat
D F M Hoary Bat
DF Western Yellow Bat
D Spotted Bat
D F M Western Big-eared Bat
DF Pallid Bat
D F M Mexican Freetail Bat
DF Pocketed Freetail Bat
DF Big Freetail Bat
DF Western Mastiff Bat
D Antelope Jackrabbit
DF *Blacktail Jackrabbit
M Eastern Cottontail
DF *Desert Cottontail
D F M Rock Squirrel
DF *Yuma Antelope Ground Squirrel

D *Roundtail Ground Squirrel
F M Cliff Chipmunk
M Tassel-eared Squirrel
M Arizona Gray Squirrel
D F M Valley Pocket Gopher
DF Silky Pocket Mouse
DF Arizona Pocket Mouse
DF Hispid Pocket Mouse
D Desert Pocket Mouse
DF Rock Pocket Mouse
D Bannertail Kangaroo Rat
D Merriam Kangaroo Rat
D Ord Kangaroo Rat
D Desert Kangaroo Rat
DF Western Harvest Mouse
DF Fulvous Harvest Mouse
D Cactus Mouse
D Merriam Mouse
DF Deer Mouse
DF White-footed Mouse
F M Brush Mouse
DF Southern Grasshopper Mouse
DF Hispid Cotton Rat
DF Whitethroat Woodrat
M Mexican Woodrat
D F M Porcupine
D F M *Coyote
DF Gray Wolf
D Kit Fox
D F M Gray Fox
M Black Bear

DF Ringtail
D F M Raccoon
M Coati
DF Badger
D F M Spotted Skunk
F Striped Skunk
DF Hooded Skunk
DF Hognose Skunk
F M Jaguar
D Jaguarundi
F M Cougar
D F M Bobcat
DF *Peccary (Javelina)
DF *Mule Deer
M Whitetail Deer
DF Bighorn

Photograph Credits

Carrico, J.: 46
Coss, Harold T., Jr.: Frontispiece, 2, 6, 8, 26, 28 right, 29 left, 31, 34 left, 37
all except bottom left, 38, 40, 41, 54, 56, 62, 63, 64, 65, 66, 68, 70, 71,
73, 74, 75, 78.
Dodge, Natt N.: 32
Hoy, William: 44
Mang, Fred E., Jr.: 24, 28 left, 34 right, 37 bottom left, 39, 67, 77.
Manley, Ray: 12
Olin, George: 10, 69, 82
Steenbergh, Warren: 35, 57
Unknown: 29 right

“As the Nation’s principal conservation agency, the Department of the
Interior has basic responsibilities for water, fish, wildlife, mineral, land,
park, and recreational resources. Indian and Territorial affairs are other
major concerns of America’s Department of Natural Resources.” The
Department works to assure the wisest choice in managing all our resources
so each will make its full contribution to a better United States—now and in
the future.

National Park Service
U.S. DEPARTMENT of the INTERIOR

★ U. S. GOVERNMENT PRINTING OFFICE: 1972 O-456-399

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In the text versions only, text in italics is delimited by _underscores_.

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