RECOGNIZING THE POISONOUS KINDS
Suppose, in spite of attention to the precautions and protective measures just outlined, someone is bitten by an unidentified snake. Certainly the victim would not wish to delay treatment if the snake were poisonous, because every minute wasted would make recovery more difficult. On the other hand, he would not care to undergo either the pain associated with snake bite treatment or the anxiety following a bite if a harmless snake were the cause of the accident. Yet time and again people have been bitten by harmless snakes and have been needlessly given first aid and hospital treatment because the offending snake was incorrectly classified as poisonous. Still others have been bitten by harmless snakes and died from nothing more than fright.
When recognition of the snake is doubtful, it should, if possible, be killed and taken to a hospital or doctor’s office for correct identification. Always keep in mind, however, that a recently killed poisonous snake may still be potentially dangerous. Even after its head is cut from the body, a reptile is capable of marked reflex activity; merely touching the head may cause it to bite. To be on the safe side, use a stick to lift or carry a dead snake.
It is evident that the ability to distinguish between harmless and poisonous snakes goes hand in hand with a knowledge of proper first aid treatment. Ability to recognize a poisonous snake on sight can best be achieved by a study of live poisonous kinds and a comparison of them with harmless species. At many zoos, where both kinds are on display in glass-fronted cages, they may be examined safely. If a zoo is not conveniently near, an examination of photographs showing the different kinds is probably the next best way to become familiar with them.
It is generally considered by the layman that four kinds of poisonous snakes are found in the United States—the rattlesnake, cottonmouth, copperhead and coral snake. This grouping, although somewhat arbitrary and certainly not zoologically correct, is firmly established in the minds of most people and may very well be here to stay. Nevertheless, a more accurate and scientific approach is possible if we consider each species and subspecies as a different kind.
Illustrations in this booklet show the 16 kinds (species and subspecies) of poisonous snakes known in Texas. These photographs, together with descriptions in the text, should aid in identification. The accompanying distribution map for each form has been compiled from county records based on museum specimens, but in a few cases reliable “sight” records have been used as proof of a snake’s occurrence within a county.
Distribution of snakes within Texas is incompletely known because of a lack of reliable records; for this reason, the distribution maps are necessarily far from complete. It is hoped, however, that the lists will be brought up to date as new localities come to light. If the reader can make any additions to the present lists, he is asked to communicate with the author or to deliver specimens to the nearest large college, zoo or museum maintaining a zoological collection.
Only 16 of the approximately 106 different kinds of snakes found in the state are dangerously poisonous to man, and some are so rare that they are seldom seen. In addition, we have in Texas several species of smaller snakes known as opisthoglyphs, each possessing a mild venom and a set of small grooved fangs far back in the upper jaw. Because of their weak and limited supply of venom and small fangs, which are poorly adapted for injecting poison into large animals, these rear-fanged snakes are considered harmless to man. By far, the majority of species are small, being not more than 15 inches long and about three-sixteenths of an inch thick. In this group are the blackheaded snakes (genus Tantilla) found over most of the state. The slightly larger spotted night snakes (genus Hypsiglena) of west and central Texas have enlarged but ungrooved teeth in the upper jaw. Two Mexican rear-fanged snakes, found as far north as the Brownsville region, are somewhat larger. They are the blackstriped snake (Coniophanes imperialis imperialis) which grows to about 20 inches in length, and the Texas cat-eye snake (Leptodeira annulata septentrionalis), which reaches a length of about three feet. Still another species, the very rare Texas lyre snake (Trimorphodon vilkinsonii), is known from extreme western Texas. It is generally less than three feet long.
In spite of the small percentage of poisonous kinds of snakes in the state, it must be made clear that no one general rule can be used safely to identify all of them at a glance. It is a mistaken idea that all venomous snakes have broad, triangular heads. On the contrary, by using this rule, many of our harmless snakes look more dangerous than do some poisonous kinds. Furthermore, this generalization is made useless by several exceptions, a notable example being the coral snake which has a round head and does not look at all poisonous.
Even the characteristic rattle is not always present to make a rattlesnake’s identification certain. Sometimes the snake’s rattle is accidentally broken off, in which case this identifying appendage is gone. Then, too, a rattlesnake often is coiled in such a way that its rattles are concealed beneath a loop of its body. Again, the tell-tale rattle is not visible and it is necessary to recognize the snake by some other means.
Disregard all so-called “easy” rules by which poisonous snakes may be identified; instead, learn to know each one by its general overall appearance. For example, to identify the cottonmouth, look for a combination of its most characteristic features—relatively short, stout body and a broad, flat head. Also look for a body color of black, dark brown or olive and from 10 to 15 wide, usually indistinct, crossbands which are generally lighter in the center than on the edges. The upper jaw below the eye, as well as the lower jaw, will be light colored in contrast to the dark color above the eye. Together, these characteristics will make identification quite certain at a reasonable distance. Remember that the young of this snake are colored differently from the adults and you will not be able to identify the juvenile by using the color characteristics of the adult snake.