California Reptiles & Amphibians

Bufo alvarius - Sonoran Desert Toad

(=Ollotis alvaria)

Click on a picture for a larger view

Historical Range in California: Red

Dot-locality range map

Listen to this toad:

One short call

More sounds of
Bufo alvarius

Formerly present, now possibly extinct in California.

Adult, Yuma County, Arizona

Adult, Pima County, Arizona

Adult, Maricopa County, Arizona

Adult, Pima County, Arizona

Adult, Yuma County, Arizona
© 2004 William Flaxington

Juvenile, Pima County, Arizona

Tadpole, Graham County, Arizona
© Albert Most

Breeding Habitat, Maricopa County, Arizona

Former habitat - Imperial valley irrigation canal, Imperial County

B. alvarius was once recorded from this area between Winterhaven and the Laguna Dam in Imperial County which is now all farmland.

The toad from Yuma County, Arizona, shown above on the top left, was found one night in August on a road between two plowed agricultural fields next to this irrigation canal northeast of Yuma Arizona, about 20 miles east of California. The Sonoran Desert Toad utilized similar developed habitat in California along with undisturbed desert habitat before its disappearance in the state (see the Imperial County photos to the left.) This begs the question, why does this toad still persist in similar agricultural habitat nearby in Arizona and not in California?

Description

Size

Adults are 4 - 7 1/2 inches from snout to vent (10.1 - 19 cm). The largest toad in California (before its presumed extirpation.)

Appearance

Olive, dark brown, or dark gray, with relatively smooth skin, cranial crests, and long, large parotoid glands behind the eyes. There is a large white wart near the corner of the mouth, and large warts on the hind legs. Young have light warts set in dark spots.

Voice (Listen)

A weak, low-pitched whistling screech, 1/2 - 1 second in duration. Calls at night, following summer rains.

Behavior

Active on rainy nights, most often from May to July during summer rains. Often seen on desert roads in Arizona during the summer monsoons. Parotoid glands contain poisons which may cause paralysis and even death if ingested by dogs and, presumably, other small animals. The skin secretions have hallucinogenic properties. This is the toad involved in reports of toad licking or the smoking of dried parotoid gland secretions. Some states have passed laws against toad licking, and classify the venom of toads as a controlled substance.

Diet

This toad eats anything that it can overtake and capture, mainly a variety of invertebrates, but lizards, mice, and toads have also been observed in stomach contents.

Reproduction

Breeds late spring through early fall, May to September. Eggs are laid in still or slow-moving water, in long jelly-coated strings. Tadpoles are gray to golden brown. Metamorphosis takes place quickly, usually in less than a month.

Range

Formerly found in extreme southeast California along the Colorado River and the southern Imperial Valley. Outside California, found in southern Arizona, extreme southwest New Mexico, and in Sonora and northwest Sinaloa, Mexico.

Habitat

Sea level to 5,700 ft. (1,760 m.) Inhabits grasslands, arid desert lowlands, mountain canyons with oaks and sycamores, and pinyon-oak-juniper mountain forests. Found near springs, reservoirs, canals, streams, temporary pools, and away from water.

Taxonomic Notes

The name Colorado River Toad is also used.
This toad has been renamed Ollotis alvaria, but this nomenlature is not yet standard.

Conservation Issues (Conservation Status)

Apparently extinct in California, probably due to loss of habitat and pesticide use brought about by modern agricultural methods. According to a California Department of Fish and Game report, no toads have been collected or observed in California since 1955.

Taxonomy
Family	Bufonidae	True Toads
Genus	Bufo	True Toads
Species	alvarius	Sonoran Desert Toad
Original Description
Bufo alvarius Girard, 1859 - in Baird, Report U.S. Mex. Bound. Surv., Vol. 2, Rept., p. 26, pl. 41, figs. 1-6 from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz
Meaning of the Scientific Name
bufo - toad arius - belonging to alvus - the womb or belly from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz
Alternate Names
Colorado RiverToad Ollotis alvaria
Related or Similar California Frogs
Bufo boreas halophilus - California Toad Bufo woodhousii - Rocky Mountain Toad Bufo cognatus - Great Plains Toad Bufo punctatus - Red-spotted Toad
More Information and References
Natureserve Explorer California Dept. of Fish and Game AmphibiaWeb Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003. Behler, John L., & F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992. Degenhardt, William G., Painter, Charles W. , & Price, Andrew H. Amphibians and Reptiles of New Mexico. University of New Mexico Press, 1996 Davidson, Carlos. Booklet to the CD Frog and Toad Calls of the Pacific Coast - Vanishing Voices. Cornell Laboratory of Ornithology, 1995.

Conservation Status
The following status listings come from the Special Animals List which is published several times each year by the California Department of Fish and Game.
Organization	Status Listing
U.S. Endangered Species Act (ESA)
California Endangered Species Act (CESA)
California Department of Fish and Game	DFG:SSC	California Species of Special Concern
Bureau of Land Management
USDA Forest Service
Natureserve Global Conservation Status Ranks	G5	Secure
World Conservation Union - IUCN Red List	IUCN:LC	Least Concern