Size—This is the smallest of the copperheads, probably not reaching a length of two and one-half feet.
Young—Nothing is known of the breeding habits of this rare snake.
Distribution—This form apparently is restricted to the mountains of West Texas, where it is known in Brewster, Jeff Davis, Presidio and Terrell Counties. Until 1949 it was found sparingly throughout its range and less than a dozen specimens had been found by experienced collectors. Recently, however, students from The University of Texas obtained about 100 of these snakes during a six weeks’ summer course in a small section of Terrell County. This indicates that the Trans-Pecos copperhead is common, but in restricted areas only. Such areas generally are in wooded canyons and live oak groves where there is some leaf litter.
THE COTTONMOUTH
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
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.