Desert Tortoises (Gopherus agassizii) Fact Sheet: Summary

Kingdom: Animalia

Phylum: Chordata

Class: Reptilia

Order: Testudines - turtles, tortoises, terrapins

Family: Testudinidae - tortoises

Genus: Gopherus - gopher tortoises, North American tortoises

Species: Gopherus agassizii -Mojave desert tortoise;  Gopherus morafkai - Sonoran desert tortoise;  Gopherus evgoodei - Southern Sonoran/Northern Sinaloa desert tortoise

Body Weight
3.6-6.8 kg (8-15 lb)

Body Length
250-300 mm average; 400 mm maximum (9.8-11.8 in; 15.7 in)

Pelage
Carapace (top) brown or gray without a pattern, but often may be brown or orange in the center, especially in young.

Range
North and west of the Colorado River in the Southwestern United States in the Mojave and western Sonoran Deserts in California, southern Nevada, northwestern Arizona, and southwestern Utah

Habitat
Predominantly valleys and alluvial fans in saltbush scrub, creosote bush scrub, desert scrub, and tree yucca woodlands

IUCN Status
Critically Endangered- Gopherus agassizii (2021 assessment)
Vulnerable- Gopherus evgoodei (2018 assessment)

CITES Status
Appendix II

Other Designations
U.S. Fish & Wildlife Service: Threatened

Locomotion
Walking, can climb inclines, good diggers.

Activity Cycle
Activity patterns seasonal--rainfall and temperature influence many activities.
Most active during early spring/summer and fall (before cold weather).
Hibernate during winter.

Social Groups
Several tortoises occupy the same winter den. Burrows used by one tortoise or a breeding pair.

Diet
Mostly grasses, leafy plants, and flowers.

Predators
Of adults/juveniles: coyotes, bobcats, ravens, badgers, skunks, kit foxes
Of eggs: gila montser, badgers, skunks, kit foxes, fire ants

Sexual Maturity
From 15 years, or 190 mm carapace length, in the wild

Egg-laying
May-July
Hatchlings emerge mid-August-October

Clutch Size
Typically 4-7, range: 1-14

Interclutch Interval
Depends on environmental conditions. Every 1, 2, or 3 years.

Incubation Period
Wild populations: 90-120 days

Birth Size
Males: about 45 mm (1.8 in) carapace length
Females: 42 mm (1.7 in) carapace length

Feature Facts

• Largest terrestrial turtle in the United States
• Claws on front limbs for digging burrows and nests
• After foraging, often assume a limp, spread-eagle posture with limbs and neck extended
• Not territorial
• Communicate with head-bobbing displays, vocalizations, and odors
• Mortality in wild for juveniles more than 90%
• Diverse conservation challenges (hit by cars, competition with livestock, drought, human collection and removal); many conservation groups working to help the desert tortoise's recovery, including TFTSG, San Diego Zoo Wildlife Alliance and our partners