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.