IDENTIFICATION
The Western Diamondback Rattlesnake can be immediately identified by the 3 to 8 alternating black and white rings on the tail just forward of its rattle. There is a good deal of variation in overall coloration with the ground color varing from grayish to brown. There is a indistinct pattern of 24 to 45 brown diamond-shaped markings down the center of the back. Each of these diamonds has has a narrow light colored border. This is a heavy bodied snake with a large triangular shaped head. It has keeled scales and an undivided anal plate. The scale count at mid-body is 25 to 27.
SIZE
Adults measure 30 to 72 inches. The record size recorded for this species is 87 1/2 inches. Crotalus atrox is the largest rattlesnake native to Texas.
RANGE
The Western Diamondback Rattlesnake has a widespread range. This species is found from central Arkansas, westward across southern Oklahoma and most of Texas to southern Arizona and California. It also occurs across most of northern Mexico with some isolated populations in southern Mexico. About the only area of Texas that it is noticeably absent from is the pine woods of extreme east Texas.
DISTRIBUTION IN TEXAS
This species has been recorded from the following Texas counties: Andrews, Aransas, Archer, Armstrong, Atascosa, Bandera, Bastrop, Baylor, Bee, Bell, Bexar, Blanco, Borden, Bosque, Brazoria, Brazos, Brewster, Briscoe, Brooks, Brown, Burnet, Caldwell, Calhoun, Cameron, Clay, Coke, Comal, Commanche, Concho, Coryell, Cottle, Crockett, Crosby, Culberson, Dallam, Dallas, Dawson, Deaf Smith, DeWitt, Dickens, Dimmit, Donley, Duval, Eastland, Ector, Edwards, El Paso, Erath, Fisher, Foard, Frio, Galveston, Garza, Gillespie, Goliad, Gonzales, Guadalupe, Hardeman, Harris, Hartley, Hays, Hidalgo, Howard, Hudspeth, Hutchinson, Irion, Jack, Jackson, Jeff Davis, Jim Hogg, Jim Wells, Karnes, Kendall, Kenedy, Kent, Kerr, Kimble, King, Kinney, Kleberg, Knox, Lampasas, La Salle, Lavaca, Limestone, Live Oak, Llano, Lubbock, Lynn, Martin, Mason, Matagorda, Maverick, McCulloch, Mclennan, McMullen, Medina, Midland, Milam, Mills, Mitchell, Moore, Motley, Nolan, Nueces, Oldham, Palo Pinto, Pecos, Potter, Presidio, Randall, Real, Reeves, Refugio, San Patricio, Scurry, Shackelford, Somervell, Starr, Sterling, Stevens, Tarrant, Taylor, Terrell, Throckmorton, Tom Green, Travis, Uvalde, Val Verde, Victoria, Ward, Webb, Wilbarger, Willacy, Williamson, Wilson, Winkler, Wise, Wichita, Young, Zapata, and Zavala.
Even though there may not be records at this time, Crotalus atrox is probably found in all Texas counties west of Interstate Highway 45.
HABITAT
This is a rattlesnake of varid habitats. It is found in the lowlands and prairies and up to elevations of 5,000 feet and more. It is at home in in the desert, in rocky cliffs and canyon bottoms. It can also be found in coastal sand dunes and there have been reports of them swimming in some of the bays along the coast.
FOOD
The Western Diamondback Rattlesnake feeds on rabbits, gophers, ground squirrels, moles, rats and mice.
BEHAVIOR
An aggressive snake willing to stand its ground when distrubed or molested. In a defensive posture, the snake may raise its head and loop its neck up high above its coils giving it a better position to strike from. From such a position the snake is capable of striking more than half the length of its body.
REPRODUCTION
Courtship and breeding normally occur between March and May but there have been reports of breeding in the fall months also. Normally a female will give birth to 6 to 12 young during the summer. The young measure from 9 to 13 inches in length at birth. Occasionally the number of young born may be exceed 20.
REMARKS
Due to it's large size, potent venom, aggressive disposition and widespread range, the Western Diamondback Rattlesnake easily rates as one of the most dangerous snakes in the world. It is responsible for more serious snake bites and fatalities in Texas than any other species.
LITERATURE CITED
Brown, Bryce C. 1950. An Annotated Check List of the Reptiles and Amphibians of Texas. Baylor University Press, Waco.
Conant, R. and J.T. Collins. 1991. Reptiles and Amphibians of Eastern/Central North America, 3rd revised edition. Houghton Mifflin, Co., Boston.
Dixon, James R. 2000. Amphibians and Reptiles of Texas, 2nd edition. Texas A & M Press, College Station.
Klauber, Laurence M. 1972. Rattlesnakes: Their Habits, Life Histories, and Influence on Mankind, 2nd edition. University of California Press, Berkeley & Los Angeles.
Werler, John E., and James R. Dixon. 2000. Texas Snakes, Identification, Distribution and Natural History. University of Texas Press, Austin.
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