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Saturday, February 28, 2015

Venomous Snakes in TN

All of the venomous snakes native to Tennessee belong to the family of snakes called pit vipers.  Pit vipers are the group of venomous snakes having a specialized, heat sensing pit on the front of the head.  There are four species of pit vipers in Tennessee: CopperheadWestern CottonmouthTimber Rattlesnake and the Western Pigmy Rattlesnake.
All of our venomous snakes have a vertical, elliptical shaped eye pupil.  They are generally heavy bodied animals and because of this are not very good climbers.  They are ovoviviparous, meaning they retain the eggs within the body until the young are expelled in a membranous sac, ready to face the world.  Note:  Most water snakes are also ovoviviparous and should not be confused with the pit vipers.
Our venomous snakes have triangular shaped heads that are offset from the body, although many water snakes and hognose snakes can flatten the head making it appear somewhat triangular.
All of our venomous snakes have a single row of scales on the underside from the vent to the tip of the tail, whereas all of our non-venomous snakes have an overlapping row of two scales on the underside from the vent to the tail tip.  Note: This detail is best observed on the shed skin of a snake.
Copperhead Snake

Cottonmouth
The western cottonmouth is found west of the Tennessee River and in the counties of Cheatham, Dickson, Hickman, Humphreys, Perry, Wayne and Williamson.  Cottonmouths are fairly large (30-42 inches), heavy bodied snakes.  Found in aquatic habitats where they prey primarily upon fish and amphibians.  (They can bite when under water.)  They are often dully colored, being almost black.  While juveniles may be strongly patterned and brightly colored.  Some adults may retain the pattern which appears as hollow, hourglass shaped bands across the back of the snake.  Like the copperhead, the bands are widest on the sides and narrowest at the centerline of the back.  When confronted, they often gape to display the cottony interior of the mouth and will often stand their ground.  Note:  All Tennessee snakes have a white mouth.  When swimming their head is usually elevated above the water and their bodies appear overly buoyant, riding on the surface.  However, they can submerge in search of fish and amphibians.


Pygmy Rattlesnake

Timber Rattlesnake