Santa Cruz County, AZ
|SONORAN DESERT TOAD Incilius alvarius|
DESCRIPTION: Arizona’s largest toad, Sonoran Desert toads grow to 7.5 inches or more in length. They resemble frogs in that they have relatively smooth, typically olive-green/brown skin, but they can be identified as toads by the crests on the head (cranial crests), and prominent, elongated glands on both sides of the back of the head (parotoid glands) and on the hind legs. Young toads have small dark, orange-tipped spots on the back. Larger tadpoles are gray or brown with a rounded tail tip, and grow to about 2.25 inches.
BEHAVIOR: Most Sonoran Desert toads are found at night during the monsoon season, but they may emerge a month or more before the summer rains begin, particularly in areas of permanent water. Outside of the summer activity period, Sonoran Desert toads remain in rodent burrows or other underground retreats.
DIET: Sonoran Desert toads eat just about anything that moves and will fit into their mouths, including insects, centipedes, spiders, lizards, mice, and other amphibians.
REMARKS: The species’ skin toxins are strong enough to kill a dog and reportedly have hallucinogenic qualities. Sometimes called the “Colorado River toad”, the species has declined in western Arizona, where it has been confirmed only once on the Colorado River since 1986. A 2004 observation at a golf course in the Parker Strip indicates it still persists in the Colorado River corridor. There have been unconfirmed, recent reports from lands of the Colorado River Indian Tribes, as well. The species is apparently extirpated from southeastern California and has declined in New Mexico.
Jennings, M.R., and M.P. Hayes. 1994. Amphibian and Reptile Species of Special Concern in California. Inland Fisheries Division, California Department of Fish and Game, Rancho Cordova, CA.
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