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How to Identify Clark County, Nevada Rattlesnakes

 

Nevada is home to seven varieties of venomous reptile potentially dangerous to man. One is the Gila monster (Heloderma suspectum), the U.S.’ only venomous lizard; the remaining six are rattlesnakes.

Note: Range of each species described below extends beyond Nevada’s borders.

The Gila monster is a large, stocky lizard that typically reaches a foot or more in length when adult. It is easily distinguished by its size, its solid black snout and sharply delineated pattern of irregular red, orange or pink and black bands. A Gila monster’s skin has a distinctly bumpy or beaded look to it. The tail is round, fat and relatively short.

Despite being primarily diurnal (daytime active) in habit, because it spends the majority of its life underground the Gila monster is not commonly encountered by man. This lizard is occasionally active at night, particularly after rains. When approached, a Gila’s usual first response is to turn and move away. If threatened, however, it will face its antagonist, rise up on its legs, lift its head, open its mouth and loudly hiss. It may snap and lunge slightly forward in an attempt to ward off the attacker.

Gila monster venom is moderately toxic and may be potentially lethal to man. Bites are reported to be extremely painful but no human fatalities have been confirmed as a result of this lizard’s bite. In Nevada, Gila monsters are found across Clark, southeastern Lincoln, and extreme southern Nye counties. The Gila monster is protected by State law and may not be captured or killed without permit.

Northern and central Nevada are home to two rattlesnake varieties. The Great Basin Rattlesnake (Crotalus viridis lutosus) occupies virtually the entirety of the State from its northern border south to southern Esmeralda, central Nye and southern Lincoln counties. This generally brownish but sometimes greenish, distinctly blotched species is commonly associated with sagebrush country. In our area it typically reaches lengths of between three and four feet. The Panamint Rattlesnake (Crotalus mitchellii stephensi), identifiable by its tan or light brownish background color and the prominent dark bands across its back, inhabits the west central portion of the State, including southern Storey, central and southern Mineral, central and southern Nye and northwestern Clark (south to the Charleston Mountains) counties. It grows to lengths of between two and three feet. Ranges of the Great Basin and Panamint rattlers overlap to a great degree.

While neither Great Basin nor Panamint rattlesnake is considered ‘deadly,’ either can deliver a dangerous bite. Neither species is particularly antagonistic but either will stand its ground if cornered.

The Las Vegas Valley and adjacent Mojave Desert environments are inhabited by three rattlesnake species. The Mojave Desert Sidewinder (Crotalus cerastes cerastes), a small (rarely exceeding two feet), highly nocturnal and moderately venomous species, primarily occupies valley bottoms and other shallow sloped, relatively sandy or pebbly low elevation terrains. It is a fairly common snake whose entire Nevada range extends from about Tonopah south. Sidewinders are sometimes found coiled in the shade beneath a bush or beside a rock during the day. Typical coloration is a light tan background with prominent, dark blotches. Small protuberances over the eyes give this snake its other name – Horned Rattlesnake. It is worth noting that this is a small snake with a correspondingly small rattle. Although it may vigorously attempt to warn an intruder away, its rattle may be difficult to hear.

The creosote bush flats and alluvial fans of Clark, southern Nye and southern Lincoln counties host the Mojave Rattlesnake (Crotalus scutulatus scutulatus). This species’ highly neurotoxic (interferes with transmission of nerve impulses – most rattlesnake venoms are primarily hemotoxic, i.e., damage tissues) venom makes it among the most venomous of all rattlesnakes. In our area the Mojave is commonly referred to as the “Mojave Green,” and while its background color often does take on a subtle greenish cast this is also frequently a brownish serpent. Mojaves can reach lengths of about four feet. They display prominent light and dark diagonal stripes on the sides of their head, a distinctly outlined diamond pattern on their back and a white and black ringed tail on which the white rings are almost invariably much broader than the black. This is a potentially very dangerous snake that can and will become aggressively defensive if harassed.

Rocky hillsides upslope from the creosote flats of eastern Clark and extreme southern Lincoln counties are habitat for the Southwestern Speckled Rattlesnake (Crotalus mitchellii pyrrhus). It is closely related to the Panamint and ranges of these two snakes overlap across south central Nevada. The Southwestern speckled’s background color is highly variable and generally mimics that of surrounding rock. Color ranges from salt and pepper gray to various shades of brownish-orange and even orange or salmon. The Southwestern speckled is typically marked with muted dark blotches that gradually become bands toward the tail. This snake typically reaches lengths of between three and four feet. Although it produces a venom of just moderate toxicity, the speckled’s ability to produce and deliver large quantities of venom in a bite makes it potentially quite dangerous. Southwestern speckleds are normally, in this author’s experience, very timid. But like any animal, this animal can and will become highly defensive if aroused.

The extreme southern tip of Clark County (for all practical purposes the area from the Newberry Mountain range south) is also occupied by the Western Diamondback Rattlesnake (Crotalus atrox). This heavy bodied, frequently large (four foot individuals are not uncommon) and often easily provoked species is readily recognized by its dusty, grayish tan background color, dark diamond pattern and the prominent, black and white ‘coontail’ marks just above the rattle. Unlike the Mojave’s, the Western diamondback’s tail bands are of roughly equal width. In Nevada, Western diamondbacks seem to prefer large desert washes and brushy habitats near desert springs to the more open creosote covered areas favored by the Mojave, which shares its local range. Diamondback venom is considered only moderately toxic, but a bite from a large snake can deliver a massive dose. That coupled with the diamondback’s often “hair trigger” nature makes this a potentially very dangerous snake. Western diamondbacks are responsible for most snake bite fatalities in the United States.

Alex L. Heindl

Curator of Herpetology

Marjorie Barrick Museum of Natural History

University of Nevada, Las Vegas

Las Vegas, Nevada 89154-4009

Heindla@unlv.nevada.edu

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