Colorado River Toad

(Bufo ailaoanus)


Colorado River Toad IUCN DATA DEFICIENT (DD)


Facts about this animal

Dark olive green color and leathery skin. With a length of 11-18 cm the largest native North American species of toad with cranial crests, elongate parotid glands, raised warts on hind legs. Bufo alvarius is nocturnal and more aquatic than most toad species. It is a solitary, species, until the mating season in the summer months when large groups of toads (up to 200 males) gather at temporary pools to mate. They appear when the summer showers start and breed in the temporary pools that form after the rains begin. Males croak incessantly, but have a relatively weak call, compared to other frogs and toads. They may however also actively search for females. It eats snails, centipedes, beetles, grasshoppers, spiders, scorpions, lizards, mice, and other smaller toad species. Generally, between 7,500 and 8,000 eggs encased in a long, single tube of jelly, will be laid by the female in water and hatch in 2-12 days. The larval period is about 1 month. The tadpoles are a yellow/brown color.

Did you know?
that, if the toad is molested or bothered, it can secrete a poison (toxin is called bufotenine), which irritates the mucous membranes of most predators. This poison can affect animals as large as dogs, and can cause temporary paralysis or death. In humans it can cause powerful hallucinations when ingested and in large amounts may even be able to kill a person (“The Psychedelic Toad of the Sonoran Desert”).


Name (Scientific) Bufo ailaoanus
Name (English) Colorado River Toad
Name (French) Crapaud du Colorado
Name (German) Coloradokröte
Name (Spanish) Sapo del Colorado
CITES Status Not listed
CMS Status Not listed




Range Northern parts of Mexico, the southern parts of Arizona and New Mexico, and the southeast corner of California.
Habitat It can be found in a variety of desert and semi-arid habitats from sea-level to 1600 m: brushy desert with creosote bush and mesquite washes, semi-arid grasslands, rocky riparian zones with sycamore and cottonwoods, and oak-walnut woodlands in mountain canyons (remaining underground throughout the day, frequently in rodent burrows). It is semi-aquatic and is usually associated with large, somewhat permanent streams. It is occasionally found near small springs, temporary rain pools, human-made canals and irrigation ditches
Wild population Only one specimen has ever been collected, and this species is considered to be very rare and hard to find. The population trend is unknown (Red List IUCN 2012).
Zoo population 106 specimens reported to ISIS (2007)

In the Zoo

Colorado River Toad


How this animal should be transported

For air transport, Container Note 45 of the IATA Live Animals Regulations should be followed.


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Photo Copyright by
© Marcel Burkhard,

Why do zoos keep this animal

As an amphibian - i.e. an animal whose existence depends on the presence of water - that lives also in the desert, exhibiting this species is certainly of educational value.