Description—This moderately slender snake is very similar in color and markings to the western diamondback rattlesnake. Its body is olive green with a pattern of darker diamond shaped markings down the middle of the back. These blotches are well defined by a border of light scales. It differs from the western diamondback in having narrower black tail rings and wider white spaces between these rings. A narrow light line extends from the eye to above the angle of the mouth. Size—Average length is three feet, or shorter than the diamondback rattlesnake. Because of its more slender form, it does not appear as large as a western diamondback of equal length. Young—The average litter contains eight, the young being similar to the adults in color and marking. Distribution—The Mojave rattlesnake is known in Brewster, Hudspeth and Presidio Counties. Unlike most other rattlers, this species is reported to be most active during daylight hours. It is rather quiet by nature and does well in captivity. [Illustration: Distribution map] PRAIRIE RATTLESNAKE _Crotalus viridis viridis_ [Illustration: PRAIRIE RATTLESNAKE] Description—Color of the back is greenish or grayish. A series of dark, rounded blotches extends down the middle of the back. These markings, with narrow white borders, become wider and shorter near the tail to form bands. In front of the eye is a narrow light line which extends backward and downward to the mouth. Size—Rather slender in form, this snake reaches a maximum size of five and a half feet. Average length is three feet. Young—Broods average 12 but vary from four to 21. Distribution—Texas records of this snake are widely scattered. Counties in which it is know include: Andrews, Armstrong, Baylor, Brewster, Briscoe, Callahan, Carson, Castro, Childress, Crane, Crosby, Dallam, Dawson, Deaf Smith, Dickens, Ector, El Paso, Garza, Gray, Hansford, Hartley, Haskell, Hemphill, Hockley, Hutchinson, Kent, Lamb, Lipscomb, Lubbock, Lynn, Midland, Moore, Ochiltree, Oldham, Pecos, Potter, Presidio, Randall, Reeves, Roberts, Sherman, Taylor, Tom Green, Ward, Wheeler, Wilbarger, Winkler, and Yoakum. When aroused, this snake becomes a vicious adversary but, like most snakes, is satisfied to go its way if given half a chance. [Illustration: Distribution map] THE ELAPID SNAKES