General

Photo courtesy of Washington Department of Fish & Wildlife

VALLEY GARTER SNAKE
Thamnophis sirtalis fitchi

Identification

• Subspecies of the common garter snake.
• Medium sized snake reaching total length of up to 34 inches.
• Nearly black background color with three bright longitudinal stripes running the length of the body, underside is pale yellow or bluish gray.
• Most distinguishing characteristics of this subspecies in our region are the irregular red spots along the sides.

• Thought to be common in the past, now in decline for no apparent reason.
• Closely associated with permanent surface water.
• In Yellowstone observed only in the Falls River drainage in the Bechler region and three miles south of the south entrance along the Snake River.

• Generally active during the day.
• In the Yellowstone area it eats mostly toads, chorus frogs, fish remains, and earthworms; can eat relatively poisonous species.
• Predators include fish, birds, and
  carnivorous mammals.

WANDERING GARTER SNAKE
Thamnophis elegans vagrans

Identification

• Most common reptile in the park.
• 6 to 30 inches in length.
• Brown, brownish green, or gray with three light stripes-one running the length of the back and a stripe on each side.

• Usually found near water in all areas of the park.
• Eats small rodents, fish, frogs, tadpoles, salamanders, earthworms, slugs, snails, and leeches.

• May discharge musk from glands at the base of the tail when threatened.
• Gives birth to as many as 20 live young in late summer or fall.

BULLSNAKE
Pituophis catenifer sayi

Identification

• A subspecies of the gopher snake, is Yellowstone's largest reptile, ranging from 50 to 72 inches long.
• Yellowish with a series of black, brown, or reddish-brown blotches down the back; the darkest, most contrasting colors are near the head and tail; blotches are shaped as rings around the tail.
• Head resembles a turtle's in shape, with a protruding scale at the tip of the snout and a dark band extending from the top of the head through the eye to the lower jaw.
  

• In Yellowstone, found at lower elevations; drier, warmer climates; and open areas such as near Mammoth.
  Behavior
• Lives in burrows and eats small rodents-behavior that gave the gopher snake its name.
• Often mistaken for a rattlesnake because of its appearance and its defensive behavior: when disturbed, it will coil up, hiss loudly, and vibrate its tail against the ground,
  producing a rattling sound.

RUBBER BOA
Charina bottae

Identification

• Infrequently encountered in Yellowstone, perhaps due to its nocturnal and burrowing habits.
• One of two species of snakes in the United States related to tropical boa constrictors and pythons.
• Maximum length of 24 inches.
• Back is gray or greenish-brown, belly is lemon yellow; scales are small and smooth, making it almost velvety to the touch.
  

• Eats rodents.
• May spend great deal of time partially buried under leaves and soil, and in rodent burrows.
• Usually found in rocky areas near streams or rivers, with shrubs or trees nearby.
• Recent sightings have occurred in the Bechler region and Gibbon Meadows.

• More than 48 inches in length.
• Greenish gray to olive green, greenish brown, light brown, or yellowish with dark brown splotches down its back that are bordered in white.
  

• Only dangerously venomous snake in the park.
• Lives in the lower Yellowstone River areas of the park, including Reese Creek, Stephens Creek, and Rattlesnake Butte, where the habitat is drier and warmer than elsewhere in the park.
  

• Usually defensive rather than aggressive.
• Only two snake bites are known during the history of the park.

SAGEBRUSH LIZARD
Sceloporus graciosus graciosus

Identification

• Only lizard in Yellowstone.
• Maximum size of five inches from snout to tip of the tail; males have longer tails and may grow slightly larger than females.
• Gray or light brown with darker brown stripes on the back set inside lighter stripes on the sides, running the length of the body; stripes not always prominent and may appear as a pattern of checks down the back; underside usually cream or white.
• Males have bright blue patches on the belly and on each side, with blue mottling on the throat.
  

• Usually found below 6,000 feet but in Yellowstone lives up to 8,300 feet.
• Populations living in thermally influenced areas are possibly isolated from others.
• Most common along the lower portions of the Yellowstone River near Gardiner, Montana and upstream to the mouth of Bear Creek; also occurs in Norris Geyser Basin, Shoshone and Heart Lake geyser basins, and other hydrothermal areas.
  

• Come out of hibernation about mid May and active through mid September.
• Diurnal, generally observed during warm, sunny weather in dry rocky habitats.
• During the breeding season males do push-ups on elevated perches to display their bright blue side patches to warn off other males.
• Feed on various insects and arthropods.
• Eaten by bull snakes, wandering garter snakes, rattlesnakes and some birds.
• May shed tail when threatened or grabbed.