Male Yosemite Toads swim and hop around a meadow surrounded by melting snow.
Juvenile and adult male Yosemite Toads around a high-elevation lake.
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 by inspiring some cold and sluggish toads to call.
Adults are 1.25 - 2.74 inches from snout to vent ( 4.4 - 6.9 cm). (Stebbins, 2003)
A robust and stocky toad with dry, uniformly warty skin.
No cranial crests are present.
Paratoid glands are large, flat, and oval.
Eyes are closely set with horizontal pupils.
A dorsal stripe is very faint or absent.
Color and Pattern
Male and females are very different in appearance.
Males are pale yellowish green or olive above, with few or no dark blotches.
Females and young are heavily blotched on a light background.
The throat and belly are pale on both sexes.
Besides the differences in color and pattern described above, males are smaller than females and have fewer and smaller warts.
Young have no dorsal stripe immediately after transformation.
The bottoms of their feet is bright orange or yellow.
Tadpoles are very dark brown, possibly as a protection from ultraviolet solar radiation which is very strong at the high elevation locations inhabited by these toads
Eyes are inset from the edges of the head on the top.
The tip of the tail is rounded.
Tadpoles grow to about 1.5 inches (3.7 cm) in length before undergoing metamorphosis. (Stebbins & McGinnis 2012)
Life History and Behavior
Active mostly in daytime, usually in sunny areas, where basking in sunlight is needed to maintain an optimal body temperature.
Activity period is relatively short, from April - July, to late September - early October.
During winter, Yosemite Toads shelter in the burrows of small mammals, 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.
For defense Yosemite toads rely on
parotoid glands and warts which can secrete a poison that deters some predators.
They may also retreat into burrows or jump into water to hide from threats.
Calling males at breeding sites will defend their territory against intrusion by other males.
Kagarise Sherman and Morton (1984) estimated that females may live at least 15 years and males at least 12 years.
(Kagarise Sherman, 1980 - referenced in Davidson and Fellers, Lanoo 2005)
A long, loud, rapid musical trill, repeated at frequent intervals.
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 is aquatic.
Fertilization is external, with the male grasping the back of the female and releasing sperm as the female lays her eggs.
Amplexus is axillary - the male grabs the female around her shoulders or arpits.
The reproductive cycle is similar to that of most North American Frogs and Toads. Mature adults come into breeding condition and migrate to ponds or ditches where the males call to advertise their fitness to competing males and to females. Males and females pair up in amplexus in the water where the female lays her eggs as the male fertilizes them externally. The adults leave the water and the eggs hatch into tadpoles which feed in the water and eventually grow four legs, lose their tails and emerge onto land where they disperse into the surrounding territory.
Females are reproductively mature at 4–6 years of age, but do not breed every year.
Males first breed when they are 3–5 years old. (Kagarise Sherman, 1980 - referenced in Davidson and Fellers, Lanoo 2005)
Mating and egg-laying takes place from May to July shortly after the snow melts in shallow pools in meadows, the margins of lakes and quiet streams.
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.
Darkly-pigmented eggs are laid
in strings of single or double strands or in a radiating network several eggs deep in shallow pools and slow moving meadow streams.
Females laid an estimated 1,500 to 2,000 eggs at one location.
Eggs hatch in 10 - 12 days.
Tadpoles and Young
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, in small burrows or root tangles.
Hybridizes with A. b. halophilus in the northern part of its range. (Stebbins 2003.)
Inhabits wet mountain meadows, willow thickets, and the borders of forests, usually not more than a hundred meters from permanent water.
After breeding, males and females move from the breeding pond into meadows where they feed for 2 - 3 months before the snows return.
Endemic to California.
Found only at high elevations in the Sierra Nevada Mountains.
Most authors indicate that the distribution is from the Ebbets Pass area of Alpine County south to the Spanish Mountains area in Fresno County, but there are mentions of Yosemite Toads from farther north than Ebbets Pass: Stebbins (2003/2012) notes their northernmost range as Grass Lake, El Dorado County (just north of the Alpine County line) and there are museum specimens from 1956 taken from Fallen Leaf Lake, El Dorado County, which is just south of Lake Tahoe.
Range map information courtesy of Paul Maier, San Diego State University.
Found at elevations of
4,800 - 12,000 ft. (1,460 - 3,630 m.) (Stebbins & McGinnis, 2012)
Notes on Taxonomy
Formerly included in the genus Bufo. In 2006, Frost et al replaced the long-standing genus Bufo in North America with Anaxyrus, restricting Bufo to the eastern hemisphere. Bufo is still used in most existing references (in 2013).
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.
Proposed for Federal ESA Threatened listing 4/25/13.
Federally listed as Threatened under the Endangered Species Act 4/25/14.
In August, 2016, the U.S. Fish and Wildlife Service announced the designation of 1.8 million acres of protected critical habitat in the Sierra Nevada mountains for Rana sierrae, the Sierra Nevada Yellow-legged Frog, the northern population of Rana muscosa, the Southern Mountain Yellow-legged Frog, and Anaxyrus canorus, the Yosemite Toad. BiologicalDiversity.org
North American Toads
Bufo canorus Camp, 1916 - Univ. California Publ. Zool., Vol. 17, No. 6, p. 59
Stebbins, Robert C., and McGinnis, Samuel M. Field Guide to Amphibians and Reptiles of California: Revised Edition (California Natural History Guides) University of California Press, 2012.
Stebbins, Robert C. California Amphibians and Reptiles. The University of California Press, 1972.
Samuel M. McGinnis and Robert C. Stebbins. Peterson Field Guide to Western Reptiles & Amphibians. 4th Edition. Houghton Mifflin Harcourt Publishing Company, 2018.
Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003.
Behler, John L., and F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992.
Powell, Robert., Joseph T. Collins, and Errol D. Hooper Jr. A Key to Amphibians and Reptiles of the Continental United States and Canada. The University Press of Kansas, 1998.
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.
Storer, Tracy I. A Synopsis of the Amphibia of California. University of California Press Berkeley, California 1925.
Wright, Albert Hazen and Anna Wright. 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.
Robert C. Thomson, Amber N. Wright, and H. Bradley Shaffer. California Amphibian and Reptile Species of Special Concern. University of California Press, 2016.
The following conservation status listings for this animal are taken from the November 2020 California "Special Animals List" and the November 2020 "State and Federally Listed Endangered and Threatened Animals of California" list, both of which are produced by multiple agencies and available here: https://www.wildlife.ca.gov/Data/CNDDB/Plants-and-Animals. You can check the link to see if there are more recent lists.
If no status is listed here, the animal is not included on either list. This most likely indicates that there are no serious conservation concerns for the animal. To find out more about an animal's status you can go to the NatureServe and IUCN websites to check their rankings.
Special Animals List Notes:
1) Formerly Bufo canorus; Frost, Grant, Faivovich, Bain, Haas, Haddad, De Sá, Channing, Wilkinson, Donnellan, Raxworthy, Campbell, Blotto, Moler, Drewes, Nussbaum, Lynch, Green & Wheeler (2006. The Amphibian Tree of Life. Bulletin of the American Museum of Natural History 297: 1-370) placed this species in the genus Anaxyrus (Tschudi, 1845). The standard common name remains Yosemite toad.
2) The USFWS published a final rule on April 29, 2014, to list the Yosemite toad as Threatened. The effective date for this rule is June 30, 2014.