Colorado River Toad

Children's Zoo

3-7 inches
3-7 inches

One month
One month

Geographic Range

North America; west coast; Colorado, Arizona, New Mexico and California. Especially common in the Sonoran Desert.

Scientific Information

Scientific Name:
Incilius alvarius

Lifestyle and Lifespan

Activity Time Frame:
Sexual Dimorphism:
2-12 days
Lifespan in the Wild:
10-20 years
Lifespan in Captivity:
> 9 years




This is the largest western toad at 4-7.5 inches long. It is chunky and short-legged, with dark olive-green leathery skin above and a smooth creamy-white underside. It has a prominent cranial crests, and an enlarged whitish wart near the angle of the jaw. Both males and females have pale throats. Its vocal sac is absent or vestigial. Its voice is weak and low-pitched, resembling a ferryboat whistle.

Species Specifics

Physical Characteristics



Occurs in a variety of habitats including creosote bush ( a desert scrub), grasslands, oak-pine woodlands, thornscrub, and tropical deciduous forest.


Ranges from arid mesquite lowlands and arid grasslands into the groves in mountain canyons. Often found near permanent springs, reservoirs and streams. Ranges include southern Colorado across Arizona to extreme southwestern New Mexico. Also found in northwestern Sinaloa to extreme southeastern California.


Carnivorous. Insects, spiders, beetles, grasshoppers, lizards, rodents, and other toads.

Ecological Web

Secondary consumer. Also controls crop pests such as snails.

Activity and Behavior

Activity Pattern

Nocturnal. The Colorado River Toad remains underground during the heat of the day. Activity is stimulated by rainfall, but is not dependent on rainfall for breeding. Most active from May-July, (living in burrows under the ground during the winter). Breeding usually occurs in spring and summer. Colorado River Toads are more aquatic than most toad species.


Social Behavior

Solitary. This toad is a solitary species until the mating season in the summer months, when large groups of toads gather at temporary pools to mate.

Reproductive Behavior

Colorado River Toads appear when the summer showers start and breed in the temporary pools that form after the rains begin. Mating occurs from May to July. Males croak incessantly, but have a relatively weak call, compared to other frogs and toads. The female lays strands of black eggs. There can be as many as 8,000 eggs in a single strand! The tadpoles hatch within 2-12 days. After the breeding season is over, this toad will return to its burrow where it will spend the winter.


Born as yellow-brown tadpoles, but quickly grow into toadlets after about one month.



Not endangered in most of its range, but near extinction in California. Listed as a species of Least Concern by IUCN. However, in California the toad is classified as Endangered and in New Mexico it is considered Threatened.


Historically its range extended throughout southeastern California, though it has not been seen there since the 1970's.

Current Threats

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Fascinating Facts

Largest native toad in the United States!

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 mouths of humans, but handling the toads does not cause warts (contrary to popular belief)!

Its call is described as a 'weak, low-pitched toot, lasting less than a second.'

The toad’s toxins are very dangerous -- particularly for animals -- the toxins emitted by one toad can be enough to kill a fully grown dog. Humans have exploited this harmful toxin as a psychedelic. It is illegal to have the poison from the toad, called bufotenin, in your possession in the state of California.

What is the difference between a toad and a frog? Toads are actually a type of frog, so technically there is no difference between the two. However, when people refer to toads they are generally talking about frogs from the scientific family bufonidae. This family has stubby bodies and short back legs. They typically walk instead of hop. They also prefer drier climates and have warty, dry skin.