Skip to Main Content
It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.
San Diego Zoo Wildlife Alliance logo
San Diego Zoo Wildlife Alliance Library logo

Desert Tortoises (Gopherus agassizii) Fact Sheet: Physical Characteristics

Desert Tortoise (Gopherus agassizii)

Physical Characteristics

Body measurements

Attribute Measurement
Weight 3.6-6.8 kg (8-15 lb)
Length 250-300 mm average; 400 mm maximum
(9.8-11.8 in; 15.7 in)


Sources: Bonin et al. (2006) [length]

General Appearance

  • Largest terrestrial turtle in the United States.
  • High-domed shell allows large space for lungs and efficient thermoregulation.
  • Front limbs shovel-like.
  • Prominent growth lines on scutes (also called scales or shields)
  • Carapace (top) brown or gray without a pattern, but often may be brown or orange in the center, especially in young.
  • Plastron (underside) yellowish or brownish and is not hinged.
  • Like most turtles, on the shell have 5 vertebral scutes, 4 pairs of costal (rib) scutes, 22 scutes around the margins and a single nuchal scute.
  • Like all turtles, good hearing, but no external ear; no teeth (have beak)

Sexual Dimorphism

  • Adults sexually dimorphic with males larger than females
  • Males have concave plastron (bottom shell), longer tail, and enlarged glands under chin
    • Glands possibly exude protein-like substance during breeding season
  • Female's plastron is flat, slightly expanded towards rear

Other Physical and Physiological Characteristics

  • Limbs stocky, elephantine
    • Forelimbs somewhat flattened, hindlimbs columnar
    • The turtles in this family (Testudinidae) have no connecting web of skin between digits
  • Large cone-shaped scales on limbs
  • Light eye ring
  • Iris of eye usually greenish yellow
  • Head relatively narrow; ridges on upper jaw meeting at a sharp angle
  • Forelimbs cover opening when drawn in
  • Forelimbs have five digits; hindlimbs, four
    • Claws on front limbs for digging burrows
    • Females use claws for digging nest
    • A spur present on the hind limb.
  • Gular area (part of plastron lying beneath the extended head) slightly forked (Bonin et al 2006)
  • A single scute underneath the armpits (axillary scute). (Ernst & Lovich 2009)

Hiding in the Desert

Desert Tortoise

A desert tortoise's coloration helps camoflauge it among rocks and sand.

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.

Page Citations

Auffenberg (1974)
Bonin et al. (2006)
Ernst & Lovich (2009)
Stebbins (2003)

SDZWA Library Links