Scientific Name: Thamnophis sirtalis sirtalis
Size: 20-28 inches (50.8-71.1 cm) in length
PA Status: Abundant

Habitat Type:
Found in nearly all habitats from open talus slides, cultivated fields, open canopy deciduous and coniferous forest, swamps, marshes, and bogs to dry upland hillsides and/or human habitats. They are most often found around quarries, trash dumps, banks of ditches, canals, streams, rivers, ponds, or vacant lots, and may be found under logs, rocks, boards and other debris.

Colorations:
Adults:

• The dorsal has a vertebral stripe (may be absent) and two lateral stripes.
• The stripes are white, cream, yellow, tan, brown or grey.
• The dorsal background varies from dark green, olive, olive brown, tan, black, grey to grey brown.
• Two rows of black or red (or both) spots may or may not appear between the vertebral and lateral stripes on each side.
• The ventrals are grey, green, ivory, cream or yellow with two rows of black spots. These ventral spots may be hidden by the overlapping ventrals.
• The head is grey, olive, tan, brown, black or a reddish coloration.
• The head coloration is similar to the dorsal background.
• The supralabials have dark bars.
• The throat is light colored.
• There are a few cases of melanistic individuals throughout PA.

Juveniles:

• Similar to adults.

Characteristics:

• Medium- sized, fairly heavy-bodied species.
• The head is distinct from the body
• Dorsal scales are keeled.

Scale Counts:

• 19 scale rows at midbody and anterior
• 17 scale rows at posterior
• 128-178 ventral scales
• 52-97 subcaudals scales | 2 rows of subcaudals
• 2 nasal scales
• 1 loreal scale
• 1 preocular scale
• 3 postoculars scales
• 1+2 temporal scales
• 7 supralabials
• 10 infralabials
• Anal plate is undivided

Confused with:

• Ribbon Snake
• Shorthead Garter Snake
• Water Snake
• Queen Snake

Coloration/Pattern Photos:
Adults

Juveniles:

Range Map:

References:

• Hulse, C. and McCoy C. J. and Ellen Censky ,1998. Amphibians and Reptiles of Pennsylvania and the Northeast. 337-339pp.
• Ernst, Carl H. and Ernst, Evelyn M. ,2003. Snakes of the United States and Canada. 424-436pp.

Photo Credits:

• Jason Poston
• Bob Hamilton
• Wayne Fidler