|Sonoran desert toad (Bufo alvarius) 7.5"
Sonoran desert toad, photo by Jeff Servoss
This is the largest toad in the United States, reaching 191 mm or 7.5 inches. It is found throughout southern Arizona in Cochise, Santa Cruz, Pima, Pinal, Maricopa and Yuma counties, most often in Sonoran and Chihuahuan desert scrub terrain but also in grassland and Madrean woodlands. Its diet consists of invertebrates, lizards, small mammals and amphibians. Although it breeds in pools formed by monsoon rains, adults are frequently found far from water.
This toad poses a serious danger to household pets because of its toxic secretions that can cause paralysis and death in dogs and other vertebrates. These secretions are produced by the parotoid glands found behind the eyes and on the hind limbs. The gland is the shiny, blister-like area shown in the enlargement below.
Enlargement of photo to show parotoid gland
Owners of dogs and cats should be aware of the potential for poisoning if their pet licks or bites a Sonoran desert toad. Since there is no antidote to toad toxin, quick action by a veterinarian is often necessary to save the animal's life.
Symptoms of poisoning in pets
Toad venom is not a great risk to humans who handle them, but you should wash your hands before touching eyes, mouth or nose after touching a venomous toad.
Brennan, Thomas C. and Andrew T. Holycross. A Field Guide to Amphibians and Reptiles in Arizona. Phoenix: Arizona Game and Fish Department, 2006.