Desert Tortoise

P. Cooper

Scientific Name: Gopherus agasizii
Description: 8-15 inches. A high-domed shell. Carapace brown or horn-colored, usually without definite pattern. Plastron yellowish, without a hinge. Forelimbs covered with large conical scales; when drawn in, limbs close opening of shell. Limbs stocky. Tail short. Young: Flexible shell. Nails longer and sharper than in adult. Carapace dull yellow to light brown; shields usually with dark borders. Male: Gular shields longer than in female, and lump (chin gland) on each side of lower jaw larger.
Habitat: Completely terrestrial desert species, requiring firm, but not hard, ground for construction of burrows (in banks of washes or compacted sand); adequate ground moisture for survival of eggs and young; and herbs, grass, or cacti for food. Desert oases, riverbanks, washes, dunes, and occasionally rocky slopes. Creosote bush is often present in its habitat. Tortoise tracks consist of parallel rows of rounded dents, the direction of travel indicated by sand heaped up at the rear of each mark.
Habits: Burrows, often found at the base of bushes, have halfmoon-shaped openings and may be 3-30 feet long. Each may be occupied by one to many individuals. Short tunnels afford temporary shelter; longer ones, called dens, are used for estivation and hibernation. Feed in early morning or late afternoon. During the heat of the day they retreat to burrow. In September they may congregate in a communal den to spend the winter, becoming active again in March. When two males meet, they bob their heads rapidly, rushing toward each other and striking their gular scutes together. One of the two may be overturned. When handled they void the contents of their bladder, which can lead to desiccation.
Reproduction: Clutch of 1-15 eggs, laid May-July, with 2 or rarely 3 clutches in favorable years. Eggs are hard, chalky, elliptical or spherical. Nests are funnel-shaped; sometimes constructed inside burrow. Hatching mid-August to October. Maturity reached in 15-20 years.
Diet: Grasses.
Endangered

Sonora Mud Turtle

Scientific Name: Kinosternon sonoriense
Description: 3 1/8 - 6 1/2 inches. Lacks supraorbital ridges. Carapace has 3 lengthwise keels (except in very old individuals); 9th marginal shield not enlarged; bridge of plastron lacks lengthwise groove. Head and neck heavily mottled with contrasting light and dark markings. Male: Two patches of horny scales on inner surface of each hind leg. Tail with horny, hooked tip.
Habitat: Stream-dwelling turtle that frequents springs, creeks, ponds, and the water holes of intermittent streams. Woodlands of oaks and pinyon-juniper, or forests of ponderosa pine and Douglas fir. Occasionally foothill grasslands and desert. Usually stays in or near water.
Habits: During dry periods they may congregate in water holes.
Reproduction: Clutch of 2-9 eggs, laid May-September.
Diet: Insects, crustaceans, snails, fish, frogs, and some plant materials.

Texas Spiny Softshell

Gary M. Stoltz/USFWS

Scientific Name: Trionyx spiniferus emoryi
Description: 5-18 inches. Extremely flat turtle with a flexible, pancakelike shell that is covered with leathery skin rather than horny shields. Front edge of shell often covered with tubercles or "warts". Limbs flat and toes broadly webbed. A flexible proboscis. Whitish ridge in each nostril, on either side of median septum. Lips fleshy, concealing sharp-edged jaws. Olive-brown, brown, or grayish above, variously flecked with black, sometimes with dark eyelike spots on shell. Carapace with cream-colored border. Cream or yellowish below, unmarked. Markings tend to fade with age. Young: Carapace border conspicuous; 4-5 times wider at rear than at sides. Shell often spotted with black, sometimes profusely so. Reduced dark markings on head and limbs. Pattern of white dots confined to rear third of carapace. Male: Averages smaller than female and has a more contrasting pattern, retaining juvenile markings. Carapace with sandpaperlike texture. Tail thick and fleshy, extending beyond edge of shell. Female: tends to become blotched and mottled with age. Carapace smoother than in male and with well-developed warts along front edge.
Habitat: Primarily a river turtle attracted to quiet water with bottom of mud, sand, or gravel. Enters ponds, canals, and irrigation ditches, but generally avoids temporary water. Agile both in water and on land. Can retract head out of sight beneath its shell, among folds of neck skin.
Habits: Active all year in the south. Difficult to approach and fast-moving on land and in water. It is fond of basking on banks, logs, and floating debris.
Reproduction: 1-2, clutches of 4-33 eggs, laid May-August on sandy banks. Digs flask-shaped cavity in bank of sand or gravel exposed to full sunlight. May nest more than once a season. Hatchlings emerge late August to October or following spring.
Diet: Earthworms, snails, crayfish, insects, fish, frogs, tadpoles, and occasionally aquatic plants. Sometimes scavenges.

Sources:

Behler, John L. and F. Wayne King. National Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, Inc. 1996.

Conant, Roger and Joseph T. Collins. A Field Guide to Reptiles and Amphibians of Eastern and Central North America—Third Edition, Expanded. Houghton Mifflin Company. 1998.

Ernst, Carl H. Venomous Reptiles of North America. Smithsonian Institution Press. 1992.

Klauber, Laurence M. Rattlesnakes: Their Habits, Life Histories, and Influence on Mankind. University of California Press. 1982.

Pough, F. Harvey, Robin M. Andrews, John E. Cadle, Martha L. Crump, Alan H. Savitzky, and Kentwood D. Wells. Herpetology. Prentice Hall. 1998.

Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians—Second Edition. Houghton Mifflin Company. 1985.