Wyoming’s diverse landscape supports a modest but distinctive population of native snake species. These reptiles occupy a range of habitats, from the eastern plains and sagebrush deserts to the lower mountain slopes. Understanding and identifying the local snake fauna is beneficial for personal safety, appreciating the region’s ecological balance, and promoting conservation efforts.
Common Non-Venomous Species
The majority of snakes encountered in Wyoming are non-venomous and play an important role in controlling local pest populations. The most widespread is the Wandering Garter Snake (Thamnophis elegans), a subspecies of the Western Terrestrial Garter Snake. It is identifiable by three longitudinal stripes (typically yellow, light orange, or white) running down a body that varies from olive-green to brownish-gray.
Garter snakes possess keeled scales, giving them a slightly rough texture. They are habitat generalists, found in nearly every part of Wyoming, often near water sources. Another prominent species is the Bullsnake (Pituophis catenifer), a large, heavy-bodied serpent that can grow to over five feet in length.
The Bullsnake is generally yellow or tan, marked with dark brown or black blotches, which can lead to misidentification as a rattlesnake. It has keeled scales and often mimics a rattlesnake by vibrating its tail, though it lacks a rattle. This powerful constrictor is an effective rodent predator, commonly encountered in the eastern and northern parts of the state.
The Eastern Yellow-bellied Racer (Coluber constrictor) is another common species, known for its thin body and exceptional speed. Adults are a uniform bluish-green or olive color with a pale yellow belly. They are active diurnal hunters of insects, lizards, and small mammals, and are known for defensive behavior, often striking or attempting to bite if handled.
Identifying the Rattlesnake Presence
Wyoming is home to two venomous species, the Prairie Rattlesnake (Crotalus viridis) being the most widespread and significant for public safety. This pit viper is recognizable by the iconic rattle at the end of its tail, which it vibrates when threatened. Like all pit vipers, the Prairie Rattlesnake possesses a distinctly triangular head and heat-sensing pits between its eyes and nostrils.
Their body color varies (greenish-gray to light brown or yellow), camouflaging them within prairie and grassland environments. They feature a pattern of dark, white-bordered blotches down their back that transition into dark rings near the tail. These snakes primarily hunt during cooler parts of the day and hibernate communally in rock crevices or abandoned burrows from late fall until spring.
Encountering a rattlesnake requires maintaining a respectful distance and avoiding provocation, as they are not inherently aggressive. The other venomous species is the Midget Faded Rattlesnake (Crotalus oreganus concolor), which is much smaller, rarely exceeding 25 inches in length. This species is restricted to southern Wyoming and is notable for having a highly potent, neurotoxic venom, though bites are extremely rare.
Regional Distribution and Conservation
Snake distribution across Wyoming is highly dependent on elevation, climate, and habitat availability, leading to a non-uniform geographical spread. The Prairie Rattlesnake is primarily found in all counties east of the Continental Divide and at lower elevations in the state’s foothills and plains. Conversely, species like the Wandering Garter Snake are widely distributed, while the Midget Faded Rattlesnake is confined to specific, arid southern regions.
The Wyoming Game and Fish Department (WGFD) manages and conserves the state’s native reptile populations. This work includes monitoring population trends and identifying habitat requirements to ensure healthy ecological communities. The WGFD focuses on species of concern to prevent declines caused by habitat fragmentation or human-related disturbances.
Current management protocols prohibit the commercial take of any native amphibian or reptile without a specific permit. Although common species populations appear stable, direct killing by humans remains a limiting factor for some snakes, including the Prairie Rattlesnake. The department promotes long-term protection through research and public education.