Eastern Ratsnake

Scientific Name: Pantherophis alleghaniensis
Size: 40 -101 in. (102-257 cm) in length
Status: Abundant

Habitat:
Meadows, old fields, farmland, open wooded areas. May be found under logs, boards, and other debris.

Description:
Also commonly called Black Rat Snake. Large, heavy bodied species with weakly keeled scales. The head is distinct from the body. The upper body is black to dull brown with a trace of black blotches. In some individuals the pattern is distinct and often times may appear to be outlined in red or golden color. The coloration and pattern of Adult rat snakes can be variable. The belly is white or yellowish white with a dark checkerboard pattern. The belly color may sometimes fade from white to gray or brown towards the tail. The chin, throat and scales around the mouth are white. Young differ from adults in coloration and pattern. The upper body has a white to yellow background with a strong pattern of black gray or brown blotches. The blotches alternate with smaller blotches on the sides.

Adult Coloration:
  • The dorsal is black to dull brown with a trace of black blotches.
  • The ventral white to yellow with a dark checkerboard pattern.
  • The ventral may fade from white to grey or brown towards the tail.
  • The labial scales, chin and throat are also white.
Adult Characteristics:
  • Largest snakes in PA.
  • Large, heavy bodies species.
  • The head distinct from the body.
  • Dorsal scales are weakly keeled.
Juvenile Characteristics:
  • The dorsal background is white to yellow with a strong pattern of blotches.
  • Blotches are grey, black or brown.
  • Blotches alternate with smaller blotches on the sides.
Scale Count:
  • 23-27 scale rows at midbody
  • 25 scale rows at anterior
  • 17 or 19 scale rows near the vent
  • 218-258 ventral scales
  • 46-102 subcaudals | 2 rows of subcaudals
  • 2 nasal scales
  • 1 loreal scale
  • 1 preocular scale
  • 2 postocular scales
  • 2+3-4 temporal scales
  • 8 supralabial scales
  • 11 infralabial scales
  • Anal plate is divided or semi-divided
Range:

Juvenile Gallery:

May be Confused With:
References:
  • Hulse, C. and McCoy C. J. and Ellen Censky ,1998. Amphibians and Reptiles of Pennsylvania and the Northeast. 286-290pp
  • Ernst, Carl H. and Ernst, Evelyn M. ,2003. Snakes of the United States and Canada. 115-122pp.
Credits:
  • Jason Poston
  • Billy Brown
  • Dave Badger
  • David McBride
  • Christine Hollinger
  • Sebastian Harris
  • Kyle Fawcett
  • Nate Nazdrowicz
  • M. Anne Esbenshade
  • Brandon Hunsberger
  • Don Becker (psychoticnature.com)
  • Stephen Staedtler

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