Western Diamondback Rattlesnake Western Diamondback Rattlesnake
Crotalus atrox


34-83 7/8 " (86.4-213 cm). Largest western rattlesnake. Heavy-bodied with large head sharply distinct from neck. Back patterned with light-bordered dark diamonds or hexagonal blotches; blotches often obscured by randomly distributed small dark spots, which give back a mottled or dusky look. 2 light diagonal lines on side of face; stripe behind eye meets upper lip well in front of angle of jaw. Tail encircled by broad black and white rings. Scales keeled, in 25-27 rows.


This is one of the more dangerous rattlers, capable of delivering a fatal bite. When disturbed it usually stands its ground, lifts its head well above its coils, and sounds a buzzing warning. Take heed! Rattlesnakes, Copperheads, and Cottonmouths belong to the pit viper family (Viperidae). These dangerous snakes have a heat-sensitive sensory organ on each side of the head that enables them to locate warm-blooded prey and strike accurately, even in the dark. The curved, hollow fangs are normally folded back along the jaw. When a pit viper strikes, the fangs rapidly swing forward and fill with venom as the mouth opens. The venom is a complex mixture of proteins that acts primarily on a victim's blood tissue. If you hear a rattlesnake shaking its rattle, back away. The snake is issuing a warning, and if the warning is ignored it may bite. Pit vipers are never safe to handle. Even dead ones can retain some neurological reflexes, and "road kills" have been known to bite. How to avoid and treat snakebites


Mates late March to May and in fall; 4-25 young, 8 1/2-13" (21.5-33 cm) long, are born in late summer. Females mature in 3 years.


Arid and semiarid areas from plains to mountains; brushy desert, rocky canyons, bluffs along rivers, sparsely vegetated rocky foothills; sea level to 7,000' (2,100 m).


Se. California eastward to c. Arkansas south into n. Mexico.


The "coon tail rattler" is active late in the day and at night during hot summer months. Eats rodents and birds. Record longevity is nearly 26 years.