Class Reptilia - Snakes

click to find the answer to today's question The bite of which poisonous snake in Oklahoma is commonly treated only with aspirin?

Western Copperhead Snakes are in the Order Squamata, Suborder Ophidia.

All snakes are predatory and swallow their prey whole.

Oklahoma's poisonous snakes:

The most common poisonous snake across the state of Oklahoma is the western (southern) copperhead, Agkistrodon contortrix, pictured at right. The eastern (northern) copperhead link to a local picture is also found in the eastern quarter of the state.

All poisonous snakes in Oklahoma are pit vipers. link to a local picture The name comes from an opening between the eye and nose that leads to a heat-sensing organ. These snakes do not have good eyesight. They locate prey by following scent and then picking up its body heat.

The notorious cotton mouth water moccasin, Agkistrodon piscivorous, is found in the southern part of Oklahoma. It inhabits warm, swampy areas which are not found in the central and northern parts of the state. The cotton mouth gets its name for the white color link to a local picture of the inside of its mouth. There are several things to notice about the snake in this picture. The algae giving it the green color is an indication of the very warm and moist habitat of the snake. The picture is that of a mature adult. Notice that it is not very long (about 3 feet), but its diameter is quite large. Notice that the tail is short, tapering quickly from the body. Young cotton mouths have a mottled coloration similar to a copperhead, but the adults are almost uniform brown to black.

Many people will see a snake swimming in the water and call it a water moccasin. But most of these sightings are of the common water snake, Natrix sipedon. link to a local picture The Natrix in this picture is longer than the cotton mouth in the earlier picture, but its diameter is obviously less. Notice that the tail is long, tapering slowly from the body. The Natrix is aggressive, especially when threatened. Although it is not poisonous and has no fangs, it does have several rows of sharp teeth and WILL bite.

Oklahoma is home to several types of rattlesnakes, two of which are quite small. The smallest is the pigmy rattlesnake, Sistrurus miliarus, which is less than two feet long. The massasauga, Sistrurus catenatus, might reach three feet in length.

The largest rattlesnake is the western diamondback,link to a local picture Crotalus atrox. Individuals are commonly reported that are over six feet in length. Although its color ranges from brown to tan to gray, it is easily identified by its tail with distinct broad black rings separated by white. The other widely distributed rattlesnake in Oklahoma is the timber rattlesnake,link to a local picture Crotalus horridus. The tail of this rattlesnake is dark, almost black, causing some people to refer to it as the "velvet-tailed" rattlesnake.

Types of snake venom:

All snake venoms contain substances destructive to tissue cells, nervous tissue and blood cells, in addition to other components which cause a wide variety of symptoms. The amount of each of these substances varies from species to species. Here are the four major chemical groups in venoms:

All poisonous snakes in Oklahoma produce mostly hemotoxic venom, a combination of the first three chemicals in the above list. Each species produces these chemicals in slightly different amounts.

Symptoms caused by the two venom groups:

What to do if bitten by a snake:

Other common snakes in Oklahoma:

Two types of kingsnakes are common in our area. The prairie kingsnake, Lampropeltis calligaster, link to a local picture is often mistaken for a copperhead because of its coloration. You can clearly see in this picture that the head of the kingsnake does not have the characteristic triangle shape of the copperhead. The coloration of the speckled kingsnake, Lampropeltis holbrooki, link to a local picture is unlike any other, making it an easy snake to identify. Kingsnakes will kill and eat other snakes, which should cause people who don't like snakes to appreciate them.

One of the largest snakes in our area is the bullsnake, Pituophis melanoleucus. link to a local picture The color of the bullsnake ranges from the tan in this picture to almost yellow.

Day 2

click to find the answer to today's question The coral snake is not scientifically recognized as living in any part of Oklahoma. We do have nonpoisonous snakes with coloration similar to that of the coral snake. How do the colorations of these Oklahoma snakes differ from the coral snake?

Snake identification:

The pattern of scale arrangement and the configuration of scales provide the most useful basis for identification. Your first step in learning to use dichotomous keys for snake identification is to become acquainted with the typical "scalation".

Click on the pictures below to enlarge.

Scales on the top of the head
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Scales on the bottom of the head
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Scales on the side of the head
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Counting the scale rows on the body
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Different snake keys might give scale row counts in different ways: Two more things about snake scales.

Research Links:

Class Reptilia










The bite of a copperhead is commonly treated only with aspirin.
Copperheads have the mildest venom of and poisonous snake in Oklahoma. The chemicals used to neutralize the bite are almost as hard on the body as the snake's venom.










The color bands on coral snakes run all the way around the body. The color bands of the nonpoisonous snakes stop at the belly scales.

coral snake   ||   scarlet kingsnake   ||   milk snake