Montana Natural Heritage Program rank: G4 S4. 



Western Terrestrial Garter Snake {Thamnophis elegans) 



Description: Adult Western Terrestrial (or Wandering) Garter Snakes are smaller in body size 

 than the Common Garter Snake, their length varying from 18-43". Three yellow longitudinal 

 stripes are present (one dorsal, two lateral), but the dorsal stripe is much narrower than that of 

 the Common Garter Snake. A distinctive feature of the Western Terrestrial Garter Snake is a 

 series of alternating black spots which run the length of the body between, and somewhat on, 

 the yellow stripes. The background color between the stripes tends to be more gray 

 compared to the dark bro\Mi found in the Common Garter Snake. The ventral surface has a 

 series of dark black/brown blotches which may cover most of the surface. The dorsal scales 

 are keeled and there are normally 8 upper labial scales. 

 Young: The coloration of yoimg snakes is similar to that of the adults; yoimg are live-bom. 



Similar species: See Common Garter Snake. 



Habitat and Habits: The habitat and habits of the Western Terrestrial Garter Snake are similar to 

 the Common Garter Snake, i.e., they are found in most habitats but are particularly common 

 around wetlands. On the study area both were seen sunning themselves on roads; one was 

 just above Dupuyer Creek, one just above Blackleaf Creek. Females give birth to 4-19 

 young during the summer (Stebbins 1985). 



Status: Western Terrestrial Garter Snakes are typically most common garter snake in the western 

 half of Montana. They are present on the study area and are probably foimd throughout the 

 area near water. Of particular interest would be the docimientation of any denning areas 

 located. 



Montana Natural Heritage Program Rank: G5 S5. 



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