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Desert Tortoise
Fast Facts
What do they look like?
Desert tortoises are slow growing reptiles, reaching 9-15 inches in length at
adulthood. They have elephantine legs tipped with claws specialized for digging. The
carapace (top shell) is rather bulky and ranges in color from light to dark brown.
Turtles and tortoises do not have teeth, but they do have sharp, horny beaks to
chomp through vegetation. Due to their long lifespan, desert tortoises take 15-20
years to reach sexual maturity. Until this time, all desert tortoises have flat plastrons.
Upon reaching sexual maturity, female plastrons remain flat while male plastrons
become slightly concave.
How do they behave?
Common Name: Desert Tortoise,
California Desert Tortoise
Scientific Name: Gopherus
agassizii
Family: Testudinidae
Order: Chelonia
Class: Reptilia
Range: Mojave and Sonoran
deserts of the Southwestern
United States
Habitat: Deserts
Desert tortoises spend the majority of their lives in burrows. A tortoise may dig
several burrows throughout its range and use them at different times of the year.
Periods of activity are usually restricted to spring and autumn months when
temperatures are more moderate. These tortoises begin hibernating between
October and November and do not emerge again until March or April.
Fighting may occur when males encounter each other. Desert tortoises are equipped
with a gular horn, a bony protrusion at the front of the plastron (bottom shell) which
males use in combat with each other. The fight ends when the dominant male has
forced the subordinate male to retreat or when he has been flipped onto his back.
What’s on the menu?
Tortoises are strictly herbivorous, unlike their omnivorous turtle cousins. Tortoises
graze on grasses, young cacti, herbs, and wildflowers. At the Zoo, they eat hay, fruits,
and vegetables.
How are they born?
Courtship and mating occur in the spring and fall. Eggs will either be laid early enough
to hatch before winter, or the female can retain the male’s sperm until the following
season. Females lay 2-3 clutches per season and deposit the clutch of 2 to 14 eggs in a
nest near her burrow. Eggs are generally the size of ping pong balls and incubate for
80 to 120 days. The temperature at which the eggs are incubated will determine the
sex of the hatchlings; males result from cooler temperatures while females from
warmer temperatures. Only a handful of hatchlings out of a hundred will survive to
adulthood. Eggs and hatchlings are often preyed upon by ravens, gila monsters,
foxes, badgers, and coyotes. As adults, they have few natural predators.
What can you do to help?
Lifespan: 50-80 years
Conservation Status: Threatened
Human activity in the desert has increased due to military, agricultural, and urban
development, off-road vehicle use, and mining. Human interaction, Upper
Respiratory Tract Disease, and predation by other animals have severely reduced wild
populations and inhibit the species’ recovery. As a threatened species, desert
tortoises are protected by law. It is unlawful to touch, harm, harass, or collect wild
specimens without permits. Many rescue organizations exist to rehabilitate injured
and confiscated animals in efforts to maintain and increase the population.