Maximum size for this rattlesnake ranges from 700 mm (28") to 1,620 mm (64") in total length excluding rattle.
Base coloration is highly variable. Individuals can be olive, straw-yellow, gray-brown, pinkish, or orange-brown. A series of large, dark blotches, often with thin white edges, runs the length of the back. Two additional rows of small blotches line each side. Facial and head markings are usually prominent and include dark bars extending from the eye to the corner of the mouth. A dark bar often extends across the top of the head between the eyes. The pupils are vertically elliptical. The dorsal scales are keeled. The neck is slender and the head is broad and triangular. On the end of the tail is a rattle composed of a series of loosely interlocking keratinous sections. A new section is added each time the snake sheds its skin.
This snake is distributed across the plateaus of northeastern Arizona south and east of the Colorado River. In Arizona it is found at elevations ranging from ca. 4,500' to about 9,000'.
The Prairie Rattlesnake is found in Great Basin Desertscrub, Plains and Great Basin Grassland, and lower reaches of Great Basin Conifer Woodland communities. It is often encountered near features such as rock outcroppings and low ridges but it is also encountered on vast, relatively featureless plains.
It is primarily nocturnal and crepuscular during the hot summer months and diurnal in spring and on mild or overcast summer days. It hibernates alone or in a group den during the cold months of late fall and winter. Like the other "pit-vipers" (members of the subfamily Crotalinae) this snake uses heat sensing pits (one on each side of the face between the eye and nostril) to detect warm-blooded predators and prey.
The Prairie Rattlesnake feeds on mice, other small mammals, birds, and lizards. It uses venom injected through long, hollow, retractable fangs to kill and begin digesting its prey.
Mating takes place in July and August. Young are born in summer.
SUBSPECIES FOUND IN AZ:
HOPI RATTLESNAKE Crotalus viridis nuntius. This subspecies is usually small (up to 28") and has variable coloration. Specimens can be tan, gray, gray-brown, pinkish-brown, orange-brown, or yellowish-tan.
GREEN PRAIRIE RATTLESNAKE Crotalus viridis viridis. This subspecies is larger (up to 64") and is usually tan or yellow-brown with brown blotches. Some specimens are olive or greenish-gray.
This rattlesnake is capable of delivering large amounts of potent venom. If encountered it should be left alone. A large percentage of envenomations occur when a snake is handled or abused.