Colorado River Toad


ORDER: Anura

FAMILY: Bufonidae

GENUS: Bufo

SPECIES: alvarius

DESCRIPTION:
Chunky and short-legged. This is the largest western toad at 4-7 ½ inches. It is dark brown, olive or gray above with smooth skin, prominent cranial crests, and an enlarged whitish wart near the angle of the jaw. Both male and female have pale throats. Vocal sac is absent or vestigial. Voice is weak and low-pitched, resembling a ferryboat whistle.

GEOGRAPHICAL RANGE AND HABITAT:
Ranges from arid mesquite lowlands and arid grasslands into the groves in mountain canyons. Often found near permanent springs, reservoirs, streams. Ranges include Southern Colorado across Arizona to extreme southwestern New Mexico to northwestern Sinaloa, also extreme south eastern California.

DIET:
Carnivorous. Insects, spiders, lizards, rodents, other toads.

LIFE CYCLE/SOCIAL STRUCTURE:
Nocturnal. Activity is stimulated by rainfall, but is not dependent on rainfall for breeding. Most active May-July. Breeding usually occurs in spring and summer.

SPECIAL ADAPTATIONS:
All male toads develop brown nuptial pads on the thumb and inner fingers that help them cling to the slippery body of the female during amplexus.

INTERPRETIVE INFORMATION:
Also known as the Sonoran Desert Toad. Parotid glands (located just behind the eyes) and warts secrete a sticky white poison, which in some Bufo species (including this one) can paralyze or kill dogs and other predators. Many animals, however, eat toads with no ill effect. The skin secretion may irritate the eyes or mouth of humans, but handling toads does not cause warts. Many toads have rough, highly granular skin, but this toad has leathery or relatively smooth skin.

OUR ANIMALS:
The Colorado River Toad can be found in the RAD Room in the Wayne and Gladys Valley Children's Zoo.

STATUS IN WILD:
Not endangered in most of range, but near extinction in California. Listed as a species of Least Concern by IUCN.

BIBLIOGRAPHY:

  1. Badger, David. Frogs. 1997. Barnes & Noble Publishers.
  2. eNature
  3. Stebbins, Robert. 1985. Western Reptiles and Amphibians. Houghton Mifflin, Boston, MA. p.68-69.