Only one kind of cottonmouth is found in Texas. It is one of our
heaviest and largest poisonous snakes and may reach a length of more
than five feet. When viewed from above, the head appears triangular
shaped and from the side the head looks flat on top.
The eye pupils, as with all members of the pit viper sub-family, are
elliptical.
WESTERN COTTONMOUTH
_Agkistrodon piscivorus leucostoma_
[Illustration: WESTERN COTTONMOUTH]
Description—This is the most variable poisonous snake in the state, both
in color and in the presence or absence of markings. Adults are much
less brilliantly marked than are the young or newborn snakes. Adults
have a background of dark brown and are marked by from 10 to 15 dark,
wide crossbands somewhat lighter in the center than at the edges. The
bands, which have irregular edges, become a little wider along the
sides. However, not all cottonmouths look like this. While some
individuals have clearly defined crossbands, others have none. There is
also considerable variation in color. Some cottonmouths are brown; some
are olive brown or olive green; and some are entirely black. The lower
jaw, as well as the upper jaw below the eye, is light in contrast to the
dark color on top of the head. Young cottonmouths are vividly marked on
a background of reddish-brown, highlighted by darker brown bands edged
with white. They look much like copperheads.
Size—In Texas, this heavy-bodied snake reaches a maximum length of about
four and a half or five feet, but the average is more nearly three feet.
Young—About eight are born in each litter. They are from six to eight
inches long at birth.
[Illustration: Distribution map]
Distribution—The cottonmouth has been reported in the following
counties: Anderson, Aransas, Atascosa, Austin, Bandera, Bexar, Bowie,
Brazos, Brazoria, Burleson, Burnet, Cass, Calhoun, Chambers, Cherokee,
Collin, Colorado, Comal, Dallas, Denton, Ellis, Falls, Fannin, Fisher,
Fort Bend, Galveston, Goliad, Gonzales, Grayson, Guadalupe, Hardin,
Harris, Harrison, Hays, Henderson, Houston, Jasper, Jefferson, Kaufman,
Kerr, Kimble, Lamar, Leon, Liberty, Limestone, Marion, Mason, Matagorda,
Maverick, McLennan, Medina, Montgomery, Morris, Nacogdoches, Newton,
Nueces, Orange, Parker, Polk, Red River, Refugio, Robertson, San
Jacinto, San Patricio, Shelby, Smith, Sterling, Tarrant, Tom Green,
Travis, Uvalde, Val Verde, Victoria, Walker, Wharton, Wilson, and Wise.
The cottonmouth is one of our largest poisonous snakes. It is
particularly abundant in the coastal marshes of southeastern Texas where
it is found along streams, ponds and lakes. Although ordinarily rather
sluggish, it immediately draws back its head and opens its mouth widely
in a threatening manner when annoyed, exposing the white tissue lining
the inside of the mouth. This characteristic pose is responsible for its
popular name. Moreover, like the copperhead, which also lacks rattles,
it has the habit of vibrating its tail when sufficiently annoyed. Thus,
when it is among dry leaves, or if the tail strikes a hard object, the
resulting sound may be similar to that made by a rattlesnake.
The name water moccasin, which is loosely applied to any and all water
snakes as well as to the cottonmouth, has resulted in a popular but
misplaced belief that all “water” snakes are poisonous. It should be
pointed out here that the cottonmouth, _Agkistrodon piscivorus
leucostoma_, is our only poisonous aquatic serpent. The several kinds of
harmless water snakes, which in some instances resemble it, are devoid
of poison. They can, at most, inflict a bite no more serious than the
scratch of a cat and these wounds require only the first aid recommended
for minor cuts.
Harmless water snakes most frequently mistaken for the cottonmouth
include the large diamondbacked water snake of central and eastern
Texas, the blotched water snake found over most of the state, and the
yellowbellied and broadbanded water snakes of eastern Texas. Most of
them are relatively heavy bodied, possess somewhat diamond shaped heads
and, although not venomous, will bite viciously if stepped upon or
handled.