Toad, Wyoming

Bufo baxteri (hemiophrys)

phylum: Chordata

class: Amphibia

order: Anura

family: Bufonidae

status: Endangered, ESA

range: USA (Wyoming)

Description and biology

The Wyoming toad is rather small, having a head and body length just over 2 inches (5 centimeters). It is dark brown, gray, or greenish in color with dark blotches. Its belly is spotted and its upper body has numerous rounded warts. Males, which tend to be smaller than females, have a darker throat. This toad eats a variety of insects, including ants and beetles.

In May, males move to breeding sites and attract females with their calls. Breeding takes place up to mid-June. After mating, a female Wyoming toad will lay 2,000 to 5,000 black eggs in jellylike strings, often tangled among vegetation. These eggs hatch within one week. A tadpole (larval state of a toad) metamorphoses, or changes, into its adult state within 4 to 6 weeks.

Habitat and current distribution

Wyoming toads are found only at a lake and its surrounding wet meadows approximately 20 miles (32 kilometers) from Laramie, Wyoming. This site has an elevation ranging from 7,000 to 7,500 feet (2,134 to 2,286 meters). In the early 1990s, biologists (people who study living organisms) estimated that no more than 100 Wyoming toads existed at this site.

These toads breed along the borders of bays, ponds, and wet meadows, where water is shallow and vegetation plentiful.

History and conservation measures

The Wyoming toad was discovered in 1946. Despite its narrow range, it seemed to exist in great numbers. In the early 1970s, its population began to decrease drastically. After leveling off, its numbers began to drop again in 1989.

Biologists do not know the exact reasons that the Wyoming toad is disappearing. They believe it may be due to a number of possibilities. Pesticides used on nearby farms may have seeped into the toad's habitat, poisoning it. The toads may have succumbed to predators such as California gulls, white pelicans, and raccoons, all of which have increased in number in the toad's range. Changes in weather conditions, bringing longer dry spells, may have affected the toad's ability to breed. Biologists do know that a bacterial infection called red leg is responsible for the most recent decline in the number of adult toads.

Current conservation efforts include protecting and monitoring the remaining Wyoming toads and their habitat. A program to breed the toads in captivity and then release them into the wild has also been established.