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 snout-vent length varying from 16-28". 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 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 brown 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. Females 

 give birth to 4-19 young during the summer (Stebbins 1985). The coloration of young snakes 

 is similar to that of the adults. 



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. Distribution records during this survey showed only a slightly greater 

 occurrence at higher elevations than the Common garter snake, but the numbers are too small 

 for a valid comparison. The highest elevation noted was 4340 ft., but they probably occur 

 much higher. 



Surveying: Surveys using mark-recapture techniques or sight surveys can be conducted in areas 

 of higher concentrations around marshes and bogs. 



Status: Western terrestrial garter snakes were found in all districts of the KNF. Their 

 populations appear to be stable. 



Montana Natural Heritage Program Rank: G5 S5. 



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