Online Field Guide to The Reptiles and Amphibians of Arizona
Male. Mohave County, Arizona
Clark County, Nevada
|AGASSIZ’S DESERT TORTOISE Gopherus agassizii|
DESCRIPTION: A large (shell up to 380 mm or 15″ in length) land tortoise with a dome-shaped carapace (top part of shell) that is marked by distinct growth rings. Coloration can be horn, orange-brown, gray-brown, or dark gray. The underside of the shell (plastron) is usually tan or yellow. The tail is short. The hind limbs are short, rounded, thick, and elephant-like. The forelimbs are flattened for digging, are longer than the hind limbs, and are armored with large, thick scales. The head is relatively small and rounded. In males the gular shields of the plastron extend out underneath the throat (see figure below). This species has a wider shell and longer gular shields than the similar looking Sonoran Desert Tortoise.
DISTRIBUTION: This tortoise occurs in far northwestern Arizona north of the Colorado River at elevations ranging from ~1,500′ to ~3,500′.
HABITAT: Primarily an inhabitant of Mohave Desertscrub but also enters Woodland communities in some areas. Inhabits valleys, alluvial fans, rocky bajadas, hillsides, and slopes.
BEHAVIOR: Primarily diurnal and crepuscular but occasionally active into the night. Agassiz’s Desert Tortoise is entirely terrestrial. It shelters and hibernates in self constructed burrows that are often excavated under bushes or large rocks. It uses its strong, paddle-like forelimbs to dig. Also shelters in naturally occurring cavities under rocks or in the banks of washes. When threatened it pulls the body and head into the shell and covers the opening with its thick, armored forelimbs.
DIET: This herbivore feeds on grasses, herbs, cacti, tree shoots, and other plant material.
REPRODUCTION: Mating takes place in spring and summer and 1 to 3 clutches of eggs are laid the following spring and summer.
By Thomas C. Brennan
PROTECTED throughout Arizona
|Brennan, T. C., & A. T. Holycross. 2006. A Field Guide to Amphibians and Reptiles in Arizona. Arizona Game and Fish Department. Phoenix, AZ
Brennan, T. C., & A. T. Holycross. 2005. A Field Guide to Amphibians and Reptiles of Maricopa County. Arizona Game and Fish Department. Phoenix, AZ
Murphy RW, Berry KH, Edwards T, Leviton AE, Lathrop A, Riedle JD (2011) The dazed and confused identity of Agassiz’s land tortoise, Gopherus agassizii (Testudines, Testudinidae) with the description of a new species, and its consequences for conservation. ZooKeys 113: 39–71. doi: 10.3897/zookeys.113.1353Stebbins, R.C. 1951. Amphibians of Western North America. University of California Press, Berkeley, CA.
Stebbins. 1985. Western Reptiles and Amphibians. Houghton Mifflin. New York, NY
Stebbins, R.C. 2003. A Field Guide to Western Reptiles and Amphibians, Third Edition. Houghton Mifflin Company, Boston, MA.
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