Common Gartersnake

A black and white striped snake in grass
Common garter snake in Yellowstone.

NPS

 

Scientific Name

Thamnophis sirtalis

Identification

  • Medium sized snake up to 34 inches long.
  • Nearly black background color with three bright 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.

Habitat

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

Behavior

  • Generally active during the day.
  • In the Yellowstone area it eats mostly toads, chorus frogs, fish remains, and earthworms; can eat relatively poisonous species. Reliance on amphibian prey may contribute to reports of declines of this species in the Greater Yellowstone Area.
  • Predators include fish, birds, and carnivorous mammals.
 
The head of a brown spotted snake among grass

Reptiles

There are six reptile species in Yellowstone.

A tan and black snake on a rocky surface

Bullsnake

Bullsnakes are often mistaken for rattlesnakes because of their appearance and behavior.

A tan and brown spotted snake with rattler in a coil

Prairie Rattlesnake

Prairie rattlesnakes are the only dangerously venomous snakes in Yellowstone.

A dark gray, tan, and white striped lizard with small spikes on gravel

Sagebrush Lizard

The sagebrush lizard is the only lizard in Yellowstone.

A brown snake on gravel next to a human hand

Rubber Boa

Rubber boas are usually found in rocky areas near streams or rivers with nearby shrubs or trees.

A white and tan striped snake with black dots on a rock

Terrestrial Gartersnake

Terrestrial gartersnakes are the most common reptile in Yellowstone.

Last updated: June 14, 2017

Contact the Park

Mailing Address:

PO Box 168
Yellowstone National Park, WY 82190-0168

Phone:

307-344-7381

Contact Us