The Reptiles and Amphibians of Arizona

Online Field Guide to The Reptiles and Amphibians of Arizona

Speckled Rattlesnake (Crotalus mitchellii) Arizona
Yavapai County, AZ

Maricopa Co., AZ

Arizona

Yavapai Co., AZ

SPECKLED RATTLESNAKE Crotalus mitchellii

Venomous

DESCRIPTION: A large rattlesnake (up to 1,295 mm or 51″ in total length excluding rattle) with extremely variable coloration. Specimens from the majority if its range in Arizona are rusty tan or dull pinkish-brown. Northwestern Arizona specimens are often pink or peach. Some specimens from the east-central part of its range in Arizona are off-white, pale gray, or pale blue-gray. Some specimens from the far southwestern part of its range in Arizona are off-white, cream, and tan. Its coloration and markings often match the rocks on which the animal lives. Markings consist of speckling and blotches that are somewhat scattered anteriorly and become more unified and band-like near the tail. The tip of the tail is usually marked with dark gray or black rings. The pupils are vertically elliptical and 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. Its large head, and dark rings on the tail-tip distinguish it from the similar looking Tiger Rattlesnake.

DISTRIBUTION: This snake is distributed across western and southwestern Arizona at elevations ranging from just above sea level along the Colorado River to about 5,000′.

HABITAT: An inhabitant of communities ranging from Sonoran Desertscrub and Mohave Desertscrub to the lower reaches of Interior Chaparral and Great Basin Conifer Woodland. It is usually found above the flats on rocky slopes, hillsides, steep bajadas, and rocky canyons.

BEHAVIOR: This ground-dweller can be active around the clock when conditions are favorable. Most sightings occur on spring mornings. It is primarily diurnal and crepuscular in spring and becomes nocturnal and crepuscular in late spring and summer. It hibernates during the cold months of late fall and winter. When encountered this snake often remains motionless, presumably to avoid detection. 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.

DIET: The Speckled Rattlesnake eats mice, rats, Chuckwalla lizards, smaller lizards, and birds. It uses venom injected through long, hollow, retractable fangs to kill and begin digesting its prey.

REPRODUCTION: Mating takes place in spring. Young are born during the summer monsoon (July and August).

REMARKS: 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.

By Thomas C. Brennan

Bartlett. 2000. Snakes of North America: Western
Region. Gulf Publishing Co. Houston, TX

Brennan, T. C., and A. T. Holycross. 2006. A Field Guide to Amphibians and Reptiles in Arizona. Arizona Game and Fish Department. Phoenix, AZ

Brennan, T. C., and A. T. Holycross. 2005. A Field Guide to Amphibians and Reptiles of Maricopa County. Arizona Game and Fish Department. Phoenix, AZ

Fowlie. 1965. The Snakes of Arizona. Azul Quinta Press, Fallbrook, California

Lowe, Schwalbe, Johnson. 1986. The Venomous Reptiles of Arizona. Nongame Branch
Arizona Game and Fish Department. Phoenix, AZ

Stebbins. 1985. Western Reptiles and Amphibians. Houghton Mifflin. New York, NY

Speckled Rattlesnake (Crotalus mitchellii) Arizona Range Map

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