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A Guide to the Amphibians
and Reptiles of California


Great Plains Toad - Anaxyrus cognatus

(Say, 1822)

(= Bufo cognatus)
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Great Plains Toad California Range Map
Range in California: Red

Dot-locality range map


Listen to this toad:

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One short call




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Great Plains Toad Great Plains Toad Great Plains Toad
Adult, Riverside County Adult, Riverside County Adult, Riverside County
Great Plains Toad Great Plains Toad Great Plains Toad
Adult, Riverside County Adult, Riverside County Adult, Imperial County
© Patrick Briggs
Great Plains Toad Great Plains Toad Great Plains Toad
Cranial crests converge at the front. Comparison of Anaxyrus cognatus on right and Anaxyrus woodhousii on left.
The cranial crests of A. cognatus point inward at the front, often coming together.
The parotoid glands of A. woodhousii are more elongated than on A. cognatus.

Breeding Adults
Great Plains Toad Great Plains Toad Great Plains Toad
Calling adult male, Riverside County Calling adult male, Riverside County Male and female in amplexus,
Riverside County
  Great Plains Toad  
  Calling males, Riverside County
 
     
Great Plains Toads From Outside California
Great Plains Toad Great Plains Toad Great Plains Toad
  Adult, Cochise County, Arizona  
Great Plains Toad Great Plains Toad  
Adult, Cochise County, Arizona  
Adult, New Mexico  
     
Habitat
Great Plains Toad Habitat Great Plains Toad Habitat Great Plains Toad Habitat
Breeding habitat, edge of irrigated field, Riverside County Breeding habitat, edge of irrigated field, Riverside County Habitat, agricultural irrigation pond, Riverside County
  Great Plains Toad Habitat  
  Irrigation canal habitat,
Imperial County
 
     
Short Video
  Great Plains Toad  
  Two male toads calling at night in Riverside County.
 
     
Description
 
Size
Adults are 2 - 4.5 inches from snout to vent ( 4.6 - 11.4 cm).(Stebbins & McGinnis, 2012)

Appearance
A large and robust toad with dry, warty skin.
Cranial crests form a boss on snout and separate widely toward the rear of the head.
A sharp tubercle is found on each hind foot.
Parotoid glands are elongated.
Pupils are horizontal.
Color and Pattern
Light brown, gray, or olive above with large, symmetrical olive, or green blotches with light borders.
May have a thin stripe along the middle of the back.
Pale whitish below usually with no spots.
Young
Young have many small red tubercles and a v-shaped crest.
Larvae (Tadpoles)
About 1 inch in total length (2.5 cm.) Beginning black in color, they gradually lighten up to a mottled gray or brown or black color.

Life History and Behavior
Activity
Adults are nocturnal. Juveniles are diurnal.
A good burrower, this toad remains underground in the daytime burrowed into loose soil.
Sometimes seen out during daylight on cloudy, rainy days.
Hibernation and Estivation
To escape winter freezes, toads burrow below the frostline. In California, they probably don't need to burrow so deep. Toads remain underground during periods of prolonged cold and heat - which can be as much as 63 - 77 percent of the year (Ewert, 1969 cited by Graves and Krupa in Lanoo 2005.) Heavy spring rain triggers emergence.
Movement
A typical toad: slow moving, often using a walking or crawling motion along with short hops.
Defense
For defense, like most toads, this toad relies on parotoid glands and warts which can secrete a poison that deters some predators. They have also been observed inflating the body to avoid predation by hog-nosed snakes.
Longevity
Long-lived, from 10 to possibly 20 years.
Voice (Listen)
The call of this toad is an explosive jackhammer-like metallic trill lasting from 5 seconds to almost a minute. It can be almost deafening when heard from a close distance. Calls are made at night.
Diet and Feeding
This toad's diet consists of a variety of invertebrates, including ants, flies, centipedes, mites, and cutworms.
The prey is located by sight, then the toad lunges with a large sticky tongue to catch the prey and bring it into the mouth to eat.
Breeding
Breeding is aquatic.
Fertilization is external, with the male grasping the back of the female and releasing sperm as the female lays her eggs.

Reproduction can take place throughout the season and females may lay eggs multiple times in a single year.
Breeding and egg-laying takes place in temporary pools, slow streams, irrigation ditches, holding ponds and flooded fields.

The reproductive cycle is similar to that of most North American Frogs and Toads. Reproductive mature adults ( 2 - 5 years old - 2 years in Arizona, and probably the same in California) 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.

Throughout most of the range of this species, toads emerge from burrows after heavy spring rains and move to breeding wetlands, generally from March to September. In the irrigated agricultural lands in the desert where this toad has increased its range in California, breeding is stimulated by flooding from increased crop irrigation or temperature change, since little rain falls in the area.
Eggs
Females lay Eggs are laid in strings of either single or double rows of ova surrounded by transparent jelly.
Egg strings are attached to debris in clear, shallow, water with little current.
According to one expert (Krupa, 1994) egg laying usually begins at dawn and finishes by noon.
27 Oklahoma females that were studied laid from 1,342 - 45,054 eggs, an average of 11,074. (Krupa, 1986a, cited by Graves and Krupa in Lanoo 2005).
Eggs hatch in 2 - 7 days.
Tadpoles and Young
Tadpoles graze on submerged rocks or plants feeding on plant material and decomposing invertebrate remains.
Metamorphosis takes place anywhere from 17 - 45 days after hatching, depending on water temperature and evaporation rates. Survival rate of tadpoles varies from year to year, with few surviving during a bad year.
Newly metamorphosed toads stay near their birth area for about a month or less if it dries up. They then move into agricultural fields where they can burrow into the soil, sometimes forming large aggregations.

Hybrids
Hybridizes with A. woodhousii and  rarely with A. punctatus (and outside of California with A. speciosus and A. hemiophrys.)

Habitat
Great Plains Toads inhabit creosote bush and mesquite deserts and desert scrub, prairie grasslands, sandhills, sagebrush plains, and agricultural regions, in asociation with temporary ponds, wetlands, and irrigation ponds and ditches. They are more tolerant of dry conditions than most toad species.

Geographical Range
In California, Great Plains Toads are found in the Imperial Valley in Imperial and Riverside Counties, and along the Colorado River in Imperial, Riverside, and San Bernardino Counties. They most likely spread up the Imperial Valley from the Colorado River with the development of agriculture.

The species ranges throughout the plains states east of the Rockies north into southern Canada, east to the eastern edges of Minnesota, Iowa, and Missouri, into western Texas, New Mexico, Arizona, Utah, Nevada, and into central Mexico.

Full Species Range Map
Elevational Range
Found below sea level to 8,000 ft. (2,440 m.) in elevation. (Stebbins, 2003)

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 (2014).


Alternate and Previous Names (Synonyms)

Bufo cognatus - Great Plains Toad (Stebbins 1954, 1966, 1985, 2003, Stebbins & McGinnis 2012)
Bufo cognatus - Great Plains Toad (Say's Toad, Western Toad, Plains Toad, Texas Toad, Western Plains Toad) (Wright and Wright 1949)
Bufo cognatus cognatus - Great Plains Toad (Storer 1925)
Bufo cognatus (Say 1823)

Conservation Issues  (Conservation Status)
None

Taxonomy
Family Bufonidae True Toads Gray, 1825
Genus Anaxyrus North American Toads Tschudi, 1845
Species cognatus Great Plains Toad

(Say, 1822)
Original Description
Bufo cognatus Say, 1823 - in James, Long's Exp. Rocky Mts., Vol. 2, p. 190

from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz

Meaning of the Scientific Name
Bufo - toad
Anaxyrus - Greek - A king or chief
cognatus - Latin - related by birth

Taken in part from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz

Related or Similar California Frogs
Anaxyrus boreas halophilus
Anaxyrus woodhousii

More Information and References
California Department of Fish and Wildlife

AmphibiaWeb

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.

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.

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 and the Endangered and Threatened Animals List which are published by the California Department of Fish and Wildlife.


This toad is not on the Special Animals List. There are no significant conservation concerns for it in California.

Organization
Status Listing
NatureServe Global Ranking
NatureServe State Ranking
U.S. Endangered Species Act (ESA) None
California Endangered Species Act (CESA) None
California Department of Fish and Wildlife None
Bureau of Land Management None
USDA Forest Service None
IUCN
 

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