US Geological Survey


Date of this Version



Published in Amphibian Declines: The Conservation Status of United States Species, Edited by Michael Lannoo. University of California Press, 2005.


Historically, Wyoming toads (Bufo baxteri) were abundant in the vicinity of Laramie, Albany County, Wyoming (Baxter, 1952; Corn, 1991), where they were found in the flood plains of the Big and Little Laramie rivers (Stebbins, 1985), an area of only 2,330 km2 (Lewis et al., 1985). A rapid decline was observed in the mid-1970s (Lewis et al., 1985) when they disappeared from most of their range. Surveys in the early 1980s yielded few animals, and Lewis et al. f 1985) reported their possible extinction in 1983. Wyoming toads were listed as Endangered under the Endangered Species Act in February 1984.
Currently, Wyoming toads have been reintroduced under a U.S. Fish and Wildlife Service recovery plan (Stone, 1991) to Mortenson Lake, -23 km southwest of Laramie and the site of the last known population of toads. This population has yet to return to its 1988 levels and may not be sustainable (see "Historical versus Current Abundance" below). Attempts were also made to reintroduce Wyoming toads at two locations on the Hutton Lake National Wildlife Refuge, 10 km southeast of Mortenson Lake. These animals did not establish breeding populations and all released toads disappeared. The Mortenson Lake population is considered the only known current distribution In nature for Wyoming toads (Jennings eta]., 2001).