More than one-half of all the poisonous kinds of snakes known in Texas are rattlesnakes, and records show that almost every county has at least one variety. Texas rattlesnakes range in size from the very small, 18-inch western pigmy rattlesnake, which rarely if ever causes death among humans, to the seven-foot western diamondback rattlesnake, known to be one of the most dangerous snakes in North America. All have comparatively stout bodies, facial pits characteristic of the family, and rattles. The rattle, which sets this snake apart, is a series of loosely interlocking horny segments which, when vibrated, produce a sharp buzzing sound as the segments strike against one another. A rattlesnake’s age cannot be determined by the number of segments of its rattle because a new segment is added with each shedding of the skin. Because a snake may shed several times a year, the resulting number of segments added annually may be six or more. On the other hand, the segments are frequently broken off as the rattle becomes caught in underbrush, so that few rattlesnakes have a complete rattle. WESTERN MASSASAUGA _Sistrurus catenatus tergeminus_ [Illustration: WESTERN MASSASAUGA] Description—The general body color is brown or gray. About 39 dark brown, oval blotches extend along the middle of the back while two rows of smaller blotches are found along each side. These blotches are narrowly edged with a lighter color. Size—Adults average two feet in length; larger specimens are sometimes as long as three feet. Young—The young resemble the adults but are lighter in color. Average number in a litter is eight or nine and they measure eight or nine inches at birth. Distribution—Records of this snake are widely scattered throughout the state, including the following counties: Andrews, Aransas, Armstrong, Bell, Bosque, Brazos, Calhoun, Cameron, Chambers, Clay, Colorado, Crosby, Dickens, El Paso, Gaines, Galveston, Hardeman, Haskell, Hemphill, Jim Hogg, Johnson, King, Matagorda, McLennan, Midland, Nolan, Nueces, Parker, Pecos, Roberts, Shackelford, Sutton, Tarrant, Throckmorton, Victoria, Wheeler, Wilbarger, Winkler, Yoakum, and Young. This small rattlesnake is uncommon in Texas, although years ago it was plentiful in some parts of the state. J. K. Strecker in his _Reptiles and Amphibians of Texas_, 1915, states: Mr. Luttrell of Claude, Armstrong County, informed me that he has often killed from 50 to 60 during one wheat season, but during the past four or five years he has not seen more than half a dozen a year. Wet places, usually near swamps or marshes, are its favorite habitat. One of our most docile rattlesnakes, it is seldom inclined to use its rattle, even when almost stepped upon. [Illustration: Distribution map] WESTERN PIGMY RATTLESNAKE _Sistrurus miliarius streckeri_ [Illustration: WESTERN PIGMY RATTLESNAKE]