Anaxyrus canorus (Camp, 1916)
Yosemite Toad | family: Bufonidae genus: Anaxyrus |
![]() © 2001 Joyce Gross (1 of 71)
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Description The Yosemite toad can be distinguished from its closest relative, the Western toad (Anaxyrus boreas), by its smaller size and lack of a vertebral stripe. It also has wider parotoid glands than the Western toad, with a smaller gap between the glands (Stebbins 1985). Distribution and Habitat Country distribution from AmphibiaWeb's database: United States U.S. state distribution from AmphibiaWeb's database: California
Life History, Abundance, Activity, and Special Behaviors Active in the daytime, especially during the breeding period, which starts as soon as shallow ice-melt pools form in the spring. Breeding call is a mellow, sustained, musical trill of 10-20 or more notes. Eats a variety of insects, centipedes, and spiders, and is in turn preyed upon by garter snakes, birds, and by Rana muscosa, the Mountain yellow-legged frog (Karlstrom 1962). Larva Trends and Threats Relation to Humans
Possible reasons for amphibian decline Disturbance or death from vehicular traffic Comments This toad is a member of the "boreas group" together with A. boreas (Western toad), A. exsul (Black toad), and A. nelsoni (Amargosa toad) (Blair 1964). This species was featured in News of the Week 3 June 2024: There are many iconic amphibian species around the world, and when they disappear, people notice. The Yosemite toad (Anaxyrus canorus) is endemic to California’s Sierra Nevada mountains, and suffered mass die-offs in the late 1970s. Dodge et al (2024) investigated the historical and contemporary effects of Batrachochytrium dendrobatidis (Bd), which causes a fatal amphibian disease called chytridiomycosis on the Yosemite toad. When global amphibian declines were first noticed in the 1970s and 1980s, it was decades before Bd was discovered (1998). This study used a retrospective analysis to determine Bd presence/absence on 719 museum specimens collected between 1915 and 2005, and on an additional 1,678 samples collected from live animals in the wild (2004–2012). Their study found that: 1) Bd emerged coincident with historical declines; 2) Bd is currently widely distributed throughout the species range; 3) life stage, elevation, and precipitation regime were associated with Bd infection likelihood; and, 4) the juvenile life stage was the most highly infected, with some having Bd infection loads surpassing a mortality threshold identified in other species. Thus, Bd may have played a significant yet unrecognized role in the decline of the Yosemite toad, and may continue to affect survival, recruitment, and extinction risk. These represent key insights for efforts to recover this species across its historical range and may also be important in hundreds of other species that declined before Bd was discovered. (Written by Vance Vredenburg) See another account at californiaherps.com.
References
Blair, F. W. (1964). ''Evidence bearing on the relationships of the Bufo boreas group of toads.'' Texas Journal of Science, 16(2), 181-192. Camp, C. L. (1916). ''Description of Bufo canorus, a new toad from Yosemite National Park.'' University of California Publications in Zoology, 17, 59-62. Cunningham, J. D. (1963). ''Additional observations on the ecology of the Yosemite Toad, Bufo canorus.'' Herpetologica, 19(1), 56-61. Drost, C. A., and Fellers, G. M. (1996). "Collapse of a regional frog fauna in the Yosemite area of the California Sierra Nevada, USA." Conservation Biology, 10(2), 414-425. Karlstrom, E. L. (1962). The Toad Genus Bufo in the Sierra Nevada of California: Ecological and Systematic Relationships. University of California Press, Berkeley, California. Karlstrom, E. L. (1963). ''Bufo canorus.'' Catalog of American Amphibians and Reptiles. W. J. Riemer, eds., American Society of Ichthyologists and Herpetologists, 132.1-132.2. Mullally, D. P. (1953). ''Observations on the ecology of the toad Bufo canorus.'' Copeia, 1953(3), 182-183. Sherman, C. K., and Morton, M. L. (1993). ''Population declines of Yosemite Toads in the eastern Sierra Nevada of California.'' Journal of Herpetology, 27(2), 186-198. Stebbins, R. C. (1985). A Field Guide to Western Reptiles and Amphibians. Houghton Mifflin, Boston. Originally submitted by: John Romansic and Yair Chaver (first posted 1999-02-21) Edited by: Kellie Whittaker, Michelle S. Koo (2024-06-02) Species Account Citation: AmphibiaWeb 2024 Anaxyrus canorus: Yosemite Toad <https://amphibiaweb.org/species/135> University of California, Berkeley, CA, USA. Accessed May 10, 2025.
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Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 10 May 2025. AmphibiaWeb's policy on data use. |