THE DESERT TORTOISE
The desert tortoise (Gopherus agassizii) is a gentle reptile which spends much of its life in underground burrows. The burrows are excavated by the animals to escape the harsh summer and winter weather conditions of the desert.
The animal historically occupied a range that included the desert in southeastern California, southern Nevada, western and southern Arizona, southwestern Utah, and Sonora and northern Sinaloa, Mexico. Today, the creature's populations are largely fragmented, although it can be found in declining numbers in most parts of its former range.
Tortoise emerge from their burrows in late winter or early spring and in the autumn to feed and mate.
The reptile can be active during the summer if temperatures are moderate. The desert tortoise is the largest reptile in the southwest. Unlike other reptiles which are often feared by man, the desert tortoise is an appealing creature which has become a popular pet, perhaps to its detriment. One reason for its appeal is that the animal is not a threat, but rather a vegetarian, eating a wide variety of herbaceous vegetation. One of its treats is the flower of annual plants.
Unfortunately, the slow moving reptile is vulnerable to a number of threats which could led to the demise of the species . These concerns lead to a petition to the Fish and Wildlife Service in 1984 to consider listing the desert tortoise under the Federal Endangered Species Act. Additional information on the tortoise submitted to the Service in May 1989 led to an emergency ruling listing the tortoise as endangered on August 4, 1989. After further evaluation and public hearings, the tortoise was permanently listed as threatened on April 2, 1990.
Major problems which appear to affect the tortoise in all or part of its range include:
- Loss or degradation of habitat because of off-road vehicles, military desert training maneuvers, various kinds of mineral extraction activities, grazing by cattle and sheep, and agricultural-residential development.
- Taking of individuals for pets and other forms of collection. Also, some animals have been killed outright or their shells mutilated in acts of vandalism.
- Excessive predation of juveniles by other species such as coyotes, foxes and ravens.
- Fragmentation of populations because of urbanization, highways and various rights-of-way associated with electric transmission lines, pipelines, etc.
- More recently a respiratory disease has been found in some tortoise populations, and it is suspected the disease may have been introduced by infected tortoise pets whose owners have returned them to the wild.
WHAT PROTECTION COMES WITH A LISTING
Under the provisions of the Endangered Species Act, the desert tortoise population is protected from "taking," which includes harming, killing or harassing desert tortoise or removing them from the wild. Violations are punishable by a fine and jail term. The law requires Federal agencies to consult with the Fish and Wildlife Service if a proposed project they plan to authorize, fund or carry out may affect the species. The Section 7 consultation process evaluates the impacts of the proposed action and determines whether the proposed action might jeopardize the continued existence of the species.
The Endangered Species Act -- Section 10(a)(1)(A) -- permits taking of tortoises for research. It is under this provision that the tortoises in The Desert Tortoise Conservation Center have been obtained. The tortoises in this center have been brought to this location under a joint research permit held by the Bureau of Land Management, the Nevada Department of Wildlife and The Nature Conservancy.
REPTILE AND AMPHIBIAN LIST
The Las Vegas District of the Bureau of Land Management includes about seven million acres of public lands in Clark County and parts of Lincoln and Nye counties. Scant rainfall and scarce permanent water, along with desiccating winds and high temperatures make this a harsh environment for wildlife.
As a result, amphibians, which require predictably moist environments and pooled water for the early part of their life cycle, are not prevalent. There are fewer than 10 species of frogs and toads and one of these - the Vegas Valley leopard frog (a subspecies of the relict leopard frog) - is probably now extinct.
Reptiles, which are land dwellers throughout life and have protective scales, are adapted to life in the desert. There are 20 species of lizards, 25 species of snakes and two species of turtles and tortoises in the district. Many reptiles are nocturnal, staying secluded in rock crevices near water and burrows or bushes during the day to avoid the intense summer heat. The best times to spot them are the early morning hours and near dusk. This checklist and a field guide to western reptiles and amphibians will help you identify the species in the district.
Scientific names, markings and favored habitats are included in this annotated list. Reference books used are The Audubon Society Field Guide to North American Reptiles and Amphibians, 1979; and The Biotic Communities of Southern Nevada, by W.G. Bradley and James Deacon, 1965. This list was compiled with the cooperation of the Nevada Department of Wildlife, the Nevada Natural Heritage Program and Phil Medica, an ecologist with Reynolds Electrical Engineering Company on the Nevada Test Site.
Italicized common names indicate federal listing, or candidate listing, for threatened or endangered status.
Tiger Salamander (Ambystotma tigrinum) Adults are yellow to olive green with black or brownish spots. Young are olive green. Found in permanent waters where they were introduced as fishing bait.
Woodhouse's Toad (Bufo woodhousei) Gray, olive or black above with cream below and a white dorsal stripe. Prefers sagebrush flats or sandy areas near water.
Great Basin Spadefoot (Scaphiopus intermontanus) Small, with ash gray streaks. Found in sagebrush flats and pinyon-juniper woods.
Amargosa Toad (Bufo boreas nelsoni) Green or gray with dark blotches and a white dorsal suipe. Status in Nevada is undetermined and rare.
Southwestern Toad (Bufo microscaphus) Green or brown above, buff below, light colored stripe across the head. A nocturnal species found in brooks or streams.
Red-spotted Toad (Bufo punctatus) Olive to grayish-brown with reddish orange warts. A nocturnal species found in desert streams, passes, rocky canyons, oak woodland and scrubland.
Great Plains Toad (Bufo cognates) Light brown, olive or gray with large, paired dark blotches on its back. Active at night, this burrower is found in creosote brush, desert or sagebrush flats.
Pacific Treefrog (Hyla regilla) Small frog with toe pads and black or dark brown eyestripe. Green, tan, gray, brownish or black. Found in low plant growth or rocks near streams.
Bullfrog (Rana catesbeiana) Large, olive or brown on top, whitish gray underneath with conspicuous eardrums. Very aquatic. Introduced.
Vegas Valley Leopard Frog (Rana pipiens fisheri) Slim, green frog with round, dark spots with pale borders. Found near permanent water, but probably extinct.
TURTLES AND TORTOISES
Desert Tortoise (Gopherus agassizii) Brown with a high-domed shell and stocky, scaly limbs. Found near desert pavement, washes and dunes.
Texas Spiny Softshell (Trionyx spiniferus emoryi) Flexible, flat shell. Introduced into permanent Colorado River drainage waters.
Desert Banded Gecko (Coleonyx variegatus variegatus) Pink or yellow with brown bands equal to or narrower than the interspaces. Nocturnal with vertical eye pupils. Found in rocky areas, creosote brush and pinyon-juniper.
Utah Banded Gecko (Coleonyx variegatus utahensis) Pink or yellow with brown bands wider than the interspaces, vertical eye pupils. Found in rocky areas creosote brush and pinyon-juniper.
Desert Iguana (Dipsosourus dorsalis) Gray with blotches on sides and tall and one row of enlarged scales down middle of the back. Found in creosote brush and sandy habitats.
Western Chuckwalla (Sauromalus obesus obesus) Large and dark with folds of skin on neck and sides. An uncommon species found in rocky areas.
Collared Lizard (Crotaphytus collaris) Stocky lizard with black and white collar. Found in rocky gullies and canyons.
Long-nosed Leopard Lizard (Garnbelia wislizenii wislizenii) Large lizard with leopard-like spots. Found in and plains with bunchgrass and creosote to sagebrush habitats.
Yellow-backed Spiny Lizard (Sceloporus magister uniformis) Yellowish-brown with black wedge-shaped mark on neck. Found in low-slope areas near Joshua trees, creosote and juniper.
Great Basin Fence Lizard (Sceloporus occidentalis biseriatus) Black, gray or brown with dark blotches and a blue belly. A common species found near rocks, trees, logs and buildings.
Northern Sagebrush Lizard (Sceloporus graciosus graciosus) Gray or brown with blue belly patches and black bar across the shoulders. Found in open areas near sagebrush and low shrubs at higher elevations.
Zebra-tailed Lizard (Callisaurus draconoides) Slim lizard with long tail and legs. Black and white bands on the under surface of the tail. Found in open areas on firm soil.
Side-blotched Lizard (Uto stansburiano) Brown with a black blotch on the side of the chest. A common species found near varied habitats of sand, rocks, loamy soils, grass, bushes or sparse stands of trees.
Western Brush Lizard (Urosaurus graciosus) A band of large scales down the middle of the back; tail longer than the body. Found in desert areas with loose sand.
Tree Lizard (Urosaurus ornatus) Blotched or crossbarred above with a fold of skin on each side. Spends much of the time in trees in riparian areas.
|Northern Desert Horned Lizard (Phrynosoma platyrhinos platyrhinos) Beige, reddish or gray with rows of fringed scales along both sides of the body. Found near creosote brush, cactus and sagebrush.|
Southern Desert Horned Lizard (Phrynosoma platyrhinos calidiarum) Beige, reddish or gray with rows of fringed scales along both sides of the body. Found near creosote brush, cactus and sagebrush.
Desert Night Lizard (Xantusia vigilis) Small, olive, gray or brown with tiny black spots. Lives under fallen branches of yucca and in rock crevices.
Great Basin Skink (Eumeces skilionianus utahensis) Brown, black witit white dorsal stripes. Young have a bluish tail. Found in rocky areas and woodlands.
Western Red-tailed Skink (Eumeces gilberti rubricaudatus) Olive or brown on top with varied amounts of dark spotting. Young have a reddish or bluish tail. Found in rocky areas near streams.
Great Basin Whiptail (Cnemidophorus tigris tigris) Gray, yellowish or tan with black spots or bars. Young have bluish tail. Found in open areas in sand or rocky soil
Gila Monster (Heloderma suspectum) Large, bright black and pink. A poisonous species found in deserts near washes and intermittent streams. Classified sensitive in Nevada.
Western Blind Snake (Leptotyphlops humilis) Small, with a blunt head and tail and vestigial (no longer used) eyes. Found in rocky hillsides with loose soil and near streams.
Regal Ringneck Snake (Diadophis punctatus regalis) Olive or black with orange neck ring. Prefers elevations over 2,400 feet.
Spotted Leaf-nosed Snake (Phyllorhynchus decurtatus) Small, pale pink or tan with brown blotches. An uncommon species found in sand or gravelly desert.
California Kingsnake (Lampropeltis getulus californiae) Shiny rings of black or brown and white or yellow. Found in desert and sagebrush.
Racer (Coluber constrictor) Brown or olive on top, yellow on the bottom. Found in semi-arid, open habitats. Uncommon.
Red Racer (Masticophis flagellum piceus) Reddish or pinkish with black crossbands. Found in the open desert near sand, rocks or vegetation.
Desert Striped Whipsnake (Masticophis taeniatus taeniatus) Black, brown or gray with a white stripe on each side. Found in rock outcrops at higher elevations.
Mojave patch-nosed snake (Salvadora hexalepis mojavensis) Thin, bluish to gray with yellow stripes down the back bordered by dark stripes. Large patch-like scale on nose. Found near sandy and rocky soils.
Desert Glossy Snake (Arizona elegans eburnata) Resembles a faded gopher snake. Light brown, pink or yellow with tan or gray blotches. Found in varied habitats, from barren desert to woodland.
Mojave Glossy Snake (Arizona elegans candida) Light colored with tan or gray blotches. Found in varied habitats, from barren desert to woodland.
Great Basin Gopher Snake (Pituophis melanoleucus deserticola) Large, yellow or beige with black or brown blotches. Will flatten head, inflate body, vibrate tail like a rattlesnake, and hiss when alarmed, but is not poisonous. Found in most habitats.
Western Long-nosed Snake (Rhinocheilus lecontei lecontei) Pinkish or reddish with black saddle-like rings on the back and a white belly. Found in desert and brush land areas.
Wandering Garter Snake (Thamnophis elegans vagrans) An uncommon species with a stripe down the center of its back. Found in brush lands, but is sometimes aquatic.
Ground Snake (Sonora semiannulata) Small, brightly colored snake with several color phases (plain, striped, banded). Found near sagebrush, creosote brush, willows and loose soil.
Mojave Shovel-nosed Snake (Chionactis occipitalis occipitalis) Whitish with brown or black crossbands and a shovel-like snout. An uncommon species found near sandy gullies, dunes and washes.
Nevada Shovel-nosed Snake (Chionactis occipitalis talpina) Whitish with brown or black crossbands and dark scales in the interspaces. An uncommon species found near sandy gullies, dunes and washes.
Southwestern black-headed snake (Tantillo hobartsmithi) Pale brown to olive body and a blackish head. Found near creosote, yucca or rocky hills.
Sonora Lyre Snake (Trimorphodan lambda) An uncommon species. Light brow or gray with brown blotches and a lyre-shaped mark on the top of its broad head. Found in rocky areas.
Night Snake (Hypsiglena torquata) Small gray or beige with large brown neck blotches and verticle eye pupils. Found in rocky or sandy areas.
Western Diamondback Rattlesnake (Crotalus atroz) Uncommon but recorded in the southern portion of the district near the Colorado River. Diamond-like markings on back with complete black and white bands on the tail.
Great Basin Rattlesnake (Crotalus viridis lutosus) Found in the northern portion of the district in transition zones to Great Basin Desert. Buff, yellowish, gray or tan above with dark evenly spaced blotches.
Southwestern Speckled Rattlesnake (Crotattis mitchelli pyrrhys) Cream, gray or brown to reddish to match habitat; generally has a sandy, speckled appearance. A poisonous species found in rocky areas, open brush land and pinyon-juniper.
Panamint Rattlesnake (Crotalus mitchelli stephensi) Cream, gray, or brown to reddish to match habitat. Generally has a sandy speckled appearance. A poisonous species found in rocky areas, open brush land, and pinyon-juniper.
Mojave Rattlesnake (Crotalus scutulatus) Greenish-gray with diamond-like pattern down the back, incomplete black and white bands on the tail. A poisonous species found in the desert and brush lands.
Mojave Desert Sidewinder (Crotalus cerastes cerastes) Pale tan, pinkish or gray. A poisonous species that moves sideways in an S-shaped curve. Found near fine sand or gravelly alluvium and rodent burrows.