California Reptiles & Amphibians

Bufo canorus - Yosemite Toad

(=Anaxyrus canorus)

Click on a picture for a larger view

Historical Range in California: Red

Dot-locality range map

Listen to this toad:

One short call

More sounds of
Bufo canorus

Watch short videos of this toad here.

Adult Female, Alpine County

Juvenile, Alpine County

Adult Male, Alpine County

Adult male, Alpine County

Adult Male and Female, Fresno County
© Patrick Briggs

Adults in amplexus with the female depositing her eggs, Alpine County

Amplexing pair, Fresno County with a second male underneath the female. He tried to steal the female from the other male, but the other male kicked and produced the territorial call until the second male finally retreated.

Adults in amplexus, Fresno County
© Julie Nelson

Adult male, Mono County
© Douglas Aguillard

Eggs, Alpine County

Eggs, Fresno County
© Julie Nelson

Male, Fresno County, in calling postition.

Calling male, Fresno County.

Tadpoles, Fresno County
© Julie Nelson

This adult male sat at the edge of a small trickle at the edge of a small lake in Alpine County for several hours, probably feeding on insects.

Toad in Habitat (in the center of the photo on the bank of a small creek) Alpine County

Habitat

Habitat, 8900 ft, Alpine County

Habitat, Alpine County

Two views of breeding habitat at 9200 ft. elevation in Fresno County during the breeding period.

Breeding habitat, 8900 ft., Alpine County (site of amplexing adults and eggs shown above is in shallow water at lower left)

Short Videos

This is a 20 second video of a male toad calling in the afternoon from a snow-melt pool in a high-altitude wet meadow surrounded by snow at 9200 ft. elevation in Fresno County. The air temperature was 37 degrees, but the shallow water was over 60 degrees F. due to the sun. Pacific Treefrogs and water sounds are heard in the background.

Many thanks to Stephanie Weber, aquatic biologist and toad Muse, for helping me to get this recording.

This is a short video of a male toad amplexing a female toad in Fresno County. A release call, probably made by the female, can be heard as the frogs hop together. A female typically produces this call after she has already laid her eggs and wants the male to release her.
© Julie Nelson

Description

Size

Adults are 1 3/4 - 2 3/4 inches from snout to vent ( 4.4 - 7 cm).

Appearance

Robust and stocky with dry, uniformly warty skin. No cranial crests. Large, flat oval paratoid glands. Eyes are closely set, pupils are horizontal. Dorsal stripe is very faint or absent. Sexes are colored differently. Males are pale yellowish green or olive above, with few or no dark blotches. Females and young are heavily blotched on a light background. Throat and belly is pale on both sexes.

Voice (Listen)

A long, rapid musical trill, repeated at frequent intervals.

Behavior

Active in daytime, usually in sunny areas. Activity period is relatively short, from April - July, to late September or early October. After breeding, males and females move from the breeding pond into meadows where they feed for 2 - 3 months before the snows return.
During winter, Yosemite Toads shelter in rodent burrows, willow thickets, forest edges adjoining meadows, and in clumps of vegetation near water.
Like most toads, this one is slow moving, often using a walking or crawling motion along with short hops.
Calling males at breeding sites will defend their territory from other males.
For defense, Yosemite toads rely on parotoid glands and warts which can secrete a poison that deters some predators.

Diet

Diet consists of a wide variety of invertebrates, including beetles, ants, siders, bees, wasps, flies, and millipedes. The prey is located by vision, then the toad lunges with a large sticky tongue to catch the prey and bring it into the mouth to eat.

Reproduction and Young

Reproduction is aquatic. Fertilization is external. Mating and egg-laying takes place in shallow pools and the margins of lakes or in quiet streams from May to July shortly after the snow melts. Males arrive at breeding sites a few days before females. (Males stay for 1 - 2 weeks, while females leave after a few days.) Males set up a territory in shallow water and make a trilled breeding call to attract a female. Calls are made during the day, peaking at mid day.When a female arrives, the male amplexes her and rides her to a location where she decides to lay her eggs. The male fertilizes the eggs as she lays them, then they separate.

Eggs are laid in shallow pools and slow moving meadow streams. Females laid an estimated 1,500 to 2,000 eggs at one location. Eggs are laid in single or double strands, or in a radiating network several eggs deep. Eggs hatch in 10 - 12 days.

Tadpoles metamorphosed in 52 - 63 days at one location. Tadpoles are preyed upon by other frogs, birds, diving beetles, and probably gartersnakes. Juvenile toads feed and overwinter near the breeding pond.

Range

Endemic to California. Ranges at high elevations in the Sierra Nevada Mountains, from the Ebbets Pass area of Alpine County south to the Spanish Mountains area in Fresno County.

Habitat

Inhabits wet mountain meadows, willow thickets, and the borders of forests, usually not more than a hundred meters from permanent water.
From 4,800 - 12,000 ft. (1,460 - 3,630 m.) elevation.

Taxonomic Notes

This toad has been named Anaxyrus canorus, but this nomenclature is not yet standard.
Hybridizes with B. b. halophilus in the northern part of its range.

Conservation Status

It has been estimated from population studies that the Yosemite Toad has disappeared from over 50% of its historic range, even in habitats that still appear to be unaltered. Remaining populations may not be reproducing enough to survive. One population at Tioga Pass, counted for more than 20 years, had declined by 90 percent in 1993.

The causes of the decline are unclear. Disease, degradation of habitat by grazing livestock, increased ultraviolet radiation, introduced predatory fishes, a severe 1980's drought, windborne pesticide contamination, and increased predation by Common Ravens, whose population has increasd greatly due to human activities, are all causes which are thought to have contributed to the decline.

Taxonomy
Family	Bufonidae	True Toads
Genus	Bufo	True Toads
Species	canorus	Yosemite Toad
Original Description
Bufo canorus Camp, 1916 - Univ. California Publ. Zool., Vol. 17, No. 6, p. 59 from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz
Meaning of the Scientific Name
Bufo - toad canorus - Latin for tuneful - "melodious trill uttered by this toad" - referring to the male's breeding call from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz
Alternate Names
Anaxyrus canorus
Related or Similar California Frogs
Bufo boreas boreas Bufo boreas halophilus Bufo woodhousii Bufo californicus Bufo exsul
More Information and References
NatureServe Explorer AmphibiaWeb California Department of Fish and Game Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003. Behler, John L., & F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992. Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Amphibians of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009. Elliott, Lang, Carl Gerhardt, and Carlos Davidson. Frogs and Toads of North America, a Comprehensive Guide to their Identification, Behavior, and Calls. Houghton Mifflin Harcourt, 2009. Lannoo, Michael (Editor). Amphibian Declines: The Conservation Status of United States Species. University of California Press, June 2005. Wright, Anna. Handbook of Frogs and Toads of the United States and Canada. Cornell University Press, 1949. Basey, Harold E. Discovering Sierra Reptiles and Amphibians. Yosemite Association and Sequoia Natural History Association, 1976, 1991. Davidson, Carlos. Booklet to the CD Frog and Toad Calls of the Pacific Coast - Vanishing Voices. Cornell Laboratory of Ornithology, 1995.

Conservation Status
The following status listings come from the Special Animals List which is published several times each year by the California Department of Fish and Game.
Organization	Status Listing
U.S. Endangered Species Act (ESA)	Candiidate
California Endangered Species Act (CESA)	None
California Department of Fish and Game	SSC	Species of Special Concern
Bureau of Land Management
USDA Forest Service	S	Sensitive
Natureserve Global Conservation Status Ranks	G2 S2	Imperiled
World Conservation Union - IUCN Red List	EN	Endangered

Return to the Top