Jacksonville Zoo and Gardens

Colorado River Toad

Bufonidae

Anura

Amphibia

Southwestern United States and northern Mexico

Desert and semi-arid areas often found in streams, near springs, and in canals and drainage ditches

Adult length: 7 in. (18 cm); coloration: uniformly green to greenish-gray dorsum (topside of the body) and creamy white venter (underside). Large white tubercles, or “warts,” are found at the angle of the jaw, but aside from the large parotoid glands and a few large lumps on the hind legs, this species has relatively smooth skin. Recently metamorphosed toadlets will be tan to green with orange or red spots on the dorsum.

In the wild 4 – 5 years; in captivity up to 15 years

Unknown

In the wild, they eat small rodents, insects, and small reptiles and other toad species; in the Zoo, they are fed crickets, worms and other invertebrates

IUCN – Least Concern

The Colorado River toad is carnivorous, and like many toads, it has a long, sticky tongue which aids it in catching prey. It often makes its home in rodent burrows, and is nocturnal. It has a loud, piercing call. It is a solitary species, until the mating season in the summer months when large groups of toads gather at temporary pools to mate.

Reproduction is aquatic. Males sometimes give advertisement calls, especially when few other males are present, but may rely more on mate searching. The toads generally breed in small rain pools after the summer showers start. Clutch size: average 7,500–8,000 eggs/female encased in a long, single tube of jelly, with a loose but distinct outline. Egg capsule gelatin is clear and not very adhesive; eggs are not partitioned, average 1.6 mm in diameter, and are packed between about 5–7/cm. They spend approximately one month as yellowish-brown tadpoles before moving onto the land. They grow to be up to 4–7 inches long.

If the toad is molested or bothered, it can secrete a poison which irritates the mucous membranes of most predators. This poison can affect animals as large as dogs, and can cause temporary paralysis or death.

The toad’s primary defense systems are glands that produce a poison. These parotid glands also produce 5-MeO-DMT and bufotenin for which the toad is known. The presence of these substances in the skin and poison of the toad produces death. In addition to having parotid glands, Colorado River toads possess glands resembling parotid glands on the dorsal surfaces of both fore- and hindlimbs. Musgrave (in Musgrave and Cochran, 1930) witnessed a fox terrier become paralyzed and die after picking up one of these toads in its mouth; a “police dog” (= German shepherd) became paralyzed and distressed for most of an hour after mere facial contact (see also Noble, 1931; Hanson and Vial, 1956; Wright, 1966). Symptoms of intoxication are excessive salivation, irregular heartbeat and gait, and pawing at the mouth. If a dog displays any of these symptoms, use a garden hose to rinse its mouth from back to front and consult a veterinarian.

“Psychoactive toad” is a name used for toads from which psychoactive substances from the family of bufotoxins can be derived. The skin and poison of Bufo alvarius (Colorado River toad or Sonoran Desert toad) contain 5-MeO-DMT and bufotenin. Other species contain only bufotenin. 5-MeO-DMT and bufotenin both belong to the family of hallucinogenic tryptamines. Due to these substances the skin or poison of the toads may produce psychoactive effects when ingested.

Rumors, dating from the 1970s, claimed that groups of “hippies” or teenagers were licking the psychoactive toads to get high. One version of the story has hippies in the hills of California chasing toads through the woods to get high. In another version of this urban legend, the infamous cane toad of Australia was said to be licked or ingested both by Aborigines and Australian hippies. Licking toads is not biologically practical. In order for these tryptamines to be orally activated, the human monoamine oxidase (MAO) system needs to be inhibited.

Colorado River toads are listed as Endangered by the New Mexico Department of Fish and Game (Degenhardt et al., 1996). Jennings and Hayes (1994a) commented on the status of Colorado River toads and noted that they appear to be extirpated from most or all sites in California and ” … some investigators have suggested that Colorado River toads are imperiled throughout much of [their] range …” In southern Arizona, these toads seem to be abundant at many desert localities. None of the states in which B. alvarius is (or was) indigenous - California, Arizona, and New Mexico - legally allow a person to remove the toad from the state.

This protected toad has been part of the Jacksonville Zoo’s animal collection since 2009.

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