Snakes of Kentucky

Venomous or Non-Venomous?


                Although five families or groups of snake occur in North America only two are present in Kentucky and the bordering states. The  Colubridae, or colubrids, and the Viperidae, or pit viper family. Since we are only dealing with two families and each has its own distinctive characteristics, telling a venomous snake from a non-venomous snake is quiet easy.

                Out of the 31 species (40 or so if sub-species and intergrades are counted) of snake present in Kentucky all but four belong in the colubrid Family and are our non venomous species. These include rat snakes, kingsnakes, hog-nosed snakes, water snakes, garter snakes, and several other smaller groups.

                The four venomous snakes present in Kentucky are pit vipers and are the copperhead, water moccasin or cottonmouth, timber rattlesnake, and pigmy rattlesnake. The pigmy rattlesnake is only present in Kentucky in the southern portion of the Land Between the Lakes and Trigg County areas.

                First, lets discuss a common but untrue method of identifying a venomous snake. Probably the most common statement I hear is “poisonous snakes have blunt tails”. This is an absolute untruth. All of our snakes are born with sharp tails. The only ones that have blunt tails are the ones that have lost the tip to a predator or an over-zealous housewife with a garden hoe!

                Now for the three absolute methods to tell if a Kentucky Snake is venomous or not.

1.)     Pupils; All of our colubrid (non-venomous) snakes have round pupils. All of our pit vipers (venomous) snakes have elliptical or “cats eye” shaped pupils.

2.)     Heat sensing pits; All of our pit vipers (venomous) have a pit located between the eye and the nostril on each side of the head. This pit allows the snake to see an infrared image in total darkness. This is useful as well for locating warm blooded prey such as mice. All of our colubrids (non poisonous) lack these pits.


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3.)     Tail scales; All of our our snakes have single scales across the belly until reaching the anal plate. The anal plate is the scale that covers the vent opening. The anal plate may be single or divided. All of our colubrids (non-venomous) snakes start having divided scales immediately following the anal plate. All of our pit vipers (venomous) have a series of scales that are not divided immediately following the anal plate. This may consist of a few scales or most of the tail section.



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            Last are a couple of methods that although are factual can be misleading.

1.)     Head shape; All of our pit vipers have a spade or arrow-head shaped head with a narrow neck that then widens into the main body. Most of our non venomous snakes heads are no wider than the neck and lack the spade shape. A few of our larger non-venomous snakes such as the diamond-backed water snake, appear to have a wider than usual head, add to the fact that a lot of species flatten their head and body and this trait can become misleading.

2.)     Cross section of the body; A cross section view of all our pit vipers (venomous) have a roughly triangle shaped body. Our colubrids (non-venomous) are more rounded or oval. The problem with this is that as mentioned before several of the non-venomous species flatten their body when disturbed and would then appear to have the triangle cross section.

                One interesting fact to note is if you find a shed skin that is intact it can be easily determined if it came from a poisonous or non-poisonous species. The scales on the tail section are a dead giveaway and if examined closely the pits or lack thereof on the head are also a telltale sign.

                The methods I have listed here are accurate in Kentucky and bordering states. Some other families exist in the South-West and in Coastal areas.

                Enjoy your time outdoors and remember – if you leave them alone, they will leave you alone!

By Jack Glisson

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