Timber Rattlesnake

Scientific Name: Crotalus horridus
Size: 36-60 inches (90-152 cm) in length
PA Status: Candidate Species

Habitat Type:
Upland forest with rocky outcroppings, talus slops, rock crevices,  rock ledges with vegetation, mature forest with numerous fallen logs, young forest with predominant leaf litter cover.

Colorations:
Adults:

  • There are 2 distinct patterns in PA: Yellow Phase (light) and Black Phase (dark).
  • The dorsal background is yellowish brown to dark brown.
  • The dorsal has a bold pattern of dark brown, grey to black Chevron like “V” shaped body bands and blotches.
  • The bands and blotches are set of from the background by a pale yellow to beige border.
  • The tail is unpatterned and solid grey, brown or black.
  • The bands continue to the tail.
  • The ventral is cream to yellowish brown and may be mottled with small black stipples.
  • The head has a dark stripe extending backwards from the eye to the corner of the mouth.
  • Melanistic and Albino species have been found in PA.

Juveniles:

  • Similar to adults

Characteristics:

  • Large-sized, heavy bodied species.
  • The head is large, flat and triangular in shape.
  • The head is distinct and set off from the body by a narrow neck.
  • Pupils are vertically elliptical.
  • Deep set pits between the eyes and nostrils.
  • The dorsal scales are strongly keeled.

Scale Counts:

  • 23 or 25 scale rows at midbody.
  • 25-27 scale rows at anterior.
  • 19 scale rows at posterior.
  • 154-183 ventral scales
  • 13-31 subcaudals scales | Single row of subcaudals
  • Higher than wide rostral scale
  • 2 internasal scales
  • 4 canthal scales
  • 2 supraocular
  • 2 nasal scales
  • 2 loreal scales
  • 2 preocular scales
  • several subocular scales
  • 4 postocular scales
  • several temporal scales
  • 13-15 supralabials
  • 14-16 infralabials
  • Anal plate is undivided

Confused with:

  • Massasauga

Coloration/Pattern Photos:
Adults
Timber Rattlesnake - By: Jason Poston Timber Rattlesnake - By: Jason Poston Timber Rattlesnake - By: Jason Poston
Timber Rattlesnake - By: Dave Huskins Timber Rattlesnake - By: Dave Huskins Timber Rattlesnake - By: Dave Huskins
Timber Rattlesnake - By: Dave Huskins Timber Rattlesnake - By: Dave Huskins Timber Rattlesnake - By: Dave Huskins
Timber Rattlesnake - By: Dave Huskins Timber Rattlesnake - By: Dave Huskins Timber Rattlesnake - By: Dave Huskins
Timber Rattlesnake - Den Group - By: Dave Huskins Timber Rattlesnake - Den Group - By: Dave Huskins Timber Rattlesnake - Den Group - By: Dave Huskins
Timber Rattlesnake - Den Group - By: Dave Huskins

Juveniles:
Timber Rattlesnake - Juvenile - By: Dave Huskins

Range Map:
Timber Rattler Range Map

References:

  • Hulse, C. and McCoy C. J. and Ellen Censky ,1998. Amphibians and Reptiles of Pennsylvania and the Northeast. 351-355pp.
  • Ernst, Carl H. and Ernst, Evelyn M. ,2003. Snakes of the United States and Canada. 503-509pp.

Photo Credits:

  • Jason Poston
  • Dave Huskins
  • Kyle Loucks