Desert tortoises, also known as desert
turtles or gopher tortoises, currently are
found in Arizona, California, Nevada and
Utah, as well as parts of Mexico, and in the
Mojave, Colorado, Sonoran and Sinaloan
des As the result of various human
activities over the past 150 years, tortoises
have been eliminated or reduced in large
portions of their range in California and in
areas near Las Vegas and St. George, Utah.

Desert tortoise population densities range
from just a few per square mile to more than
200 per square mile. Although the number of
desert tortoises in the world is unknown,
biologists have used estimates of between
500,000 and 2 million.

To survive the harsh environment of the
hot, dry desert, desert tortoises spend much
of the year in burrows dug under shrubs or

Desert Tortoise

Gopherus agassizit

in caves which provide protection from
extreme heat. They emerge in late winter
and early spring to feed and reproduce.
Desert tortoises eat a variety of native
plants, especially the flowers of desert
annuals and grasses, and they can survive
up to a year without water.

Desert tortoises may live more than 60

¥ They are slow to mature, not ready
to reproduce until they are 15 to 20 years
old. The breeding season varies from

year to year and across the tortoise’s
geographic range, but generally occurs in
the spring (April and May) and again in
the fall (August through October). After

3 to 4 months of incubation, the eggs hatch
and hatchlings typically seck shelter in
rodent burrows or natural cavities.
Tortoise shells remain soft for the first

5 to 10 years of their lives; therefore,

juveniles spend little time outside the
protection of their burrow.

Other than golden eagles and coyotes, adult
desert tortoises have few natural predators.
Bobcats, skunks, kit foxes, coyotes, ravens
and Gila monsters prey upon juveniles and
desert tortoise eggs. Feral dogs dig up and
destroy tortoise burrows, crush eggs, eat
javeniles and harass adults.

Since desert tortoises spend much of their
lives in shallow burrows and feed on native
plants, they are vulnerable to any activity
that disturbs the earth or changes their
habitat. One popular human activity in
particular threatens the survival of desert
: the use of off-road vehicles.
Off-road vehicles kill tortoises above and
below ground, collapse burrows, and
damage plants they use for food.

Also know as
gopher tortois
desert tortoises

are threatened by
such diverse factors
as expanding
urbanization, which
is encroaching
upon their habitat;
disturbances from
military bases such
as tank maneuvers
and explosives
testing; and
collection for

pets, food or
commercial trade.

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RRO
Wray

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Expanding urbanization is also a serious
threat to desert tortoises. Over the next few
decades, populations in large urban areas
such as Las Vegas; St. George, Utah; and
San Bernardino County, California, are
expected to increase sharply. Roads in

these areas give humans increased access to
turtle habitat; tortoises have been nearly
eliminated from either side of heavil;
traveled roads for up to a mile. Railroads
also cause problems, as tortoises can be
crushed by trains or get caught between the
tracks, overheat and die.

Proliferation of telephone and power

lines may enhance one predator’s ability to
kill tortoises. Ravens have increased
dramatically in number in parts of the desert
tortoise’s range. Poles and towers that
support utility lines provide nesting and
perch sites for ravens to spot slow-moving
juvenile tortoises.

Collection for pets, food or commercial trade
continues to deplete tortoise populations
despite federal and state laws forbidding
these activities. The expansive size of the
desert tortoise’s range makes law
enforcement difficult.

Captive tortoises released by people who no
longer want them pose health problems for

the wild population because they may carry a

highly contagious, and generally fatal, upper
respiratory-tract disease. Furthermore,
captive animals accustomed to having water,
food and shelter provided may find it difficult
to fend for themselves in the wild.

Poachers who deal in endangered plants
and animals sell tortoises to collectors.
Some desert tortoises are sold to
restaurants. If you suspect wild desert
tortoises have been illegally poached and

sold in a restaurant, contact your nearest
USS. Fish and Wildlife Service office.

Construction of military bases and test sites
in the deserts of the western United Stat
has been associated with a decline in desert
tortoise populations. Intense disturbances,
including tank maneuvers, air-to-ground
bombing, and testing of explosives, cause soil
compaction and changes in the plant
communities that adversely affect desert
tortoi Also, noise from vehicles, military
aircraft and explosions may damage their
hearing.

Exploration for minerals like gold, tungsten
and borax, and extraction of sand and gravel
occurs throughout most of the tortoise’s
range, causing further degradation of
tortoise habitat. Construction of roads,
vehicular traffic and the toxic byproducts
associated with mining also have a negative
impact on desert tortoises.

Agricultural activities including plowing,
application of fertilizers and pesticides, and
clearing of native vegetation for crops, kill
tortoises directly or indirectly by changing
their habitat. In addition, livestock trample
tortoises above ground and crush their
burrows, killing eggs and juveniles. Sheep,
for example, can strip a large area of plants
very quickly, leaving barren ground with no
food or cover, exposing tortoises to predators
and harsh desert conditions.

Litter poses a threat to desert tortoises as
well. Discarded objects such as balloons,
plastics, metal foil, and glass remain in
tortoises’ stomachs or intestines, giving a
false sense of fullness and causing
starvation. Garbage such as string or rubber
bands becomes entangled around tortoises’
heads or legs, causing infection, loss of

limbs, or strangulation. Trash also attracts
tortoise predators such as ravens, kit foxes
and coyotes.

In 1989, the U.S. Fish and Wildlife Service
gave temporary emergency protection to
the desert tortoise in the Mojave region of
the western United States. Long-term
protection replaced this temporary measure
when the Service listed the Mojave
population as threatened species under

the Endangered Species Act of 1973. While
an endangered species is considered in
danger of becoming extinct in all or a
significant portion of its range, the less dire
designation of threatened means a species
is likely to become endangered within the
foreseeable future.

Conserving desert tortoises requires
protecting the desert ecosystem as a whole.
The State of Nevada, federal agencies,
off-road vehicle user groups, the mining
industry, The Nature Conservancy, and
other groups have cooperatively developed a
30-year habitat conservation plan calling for
strengthened law enforcement, construction
and maintenance of tortoise barriers along
roadways, closure of some roads,
rehabilitation of habitat, and acquisition of
livestock grazing allotments. The plan also
designates funds for research and public
education. Continued development within
tortoise habitat is permitted as long as
development is carried out in accordance
with the plan. Under the plan, loss of habitat
must be adequately mitigated (tortoise
habitat that is lost must be replaced).

Augmenting this effort is the conservation of
approximately 540,000 acres of federal lands
within the Piute-Eldorado Desert Wildlife
Management Area to aid in the recovery of
tortoises and other desert plants and animals.

Desert tortoises may live more than 60
years. To survive the harsh environment of
the hot, dry western desert, tortoises live
underground in burrows or in caves.

U.S. Fish & Wildlife Service
http://jwww.fws.gov
July 1998