California Reptiles & Amphibians

Xenopus laevis - African Clawed Frog



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Introduced Range: Red

Dot-locality range map



Listen to this frog:


A short example





Introduced - not native to California

Adult and Juvenile, Orange County
© 2004 William Flaxington
Juvenile, Orange County
© 2004 William Flaxington
Captive Adult in aquarium
Captive Adults © William Leonard
Adult, San Diego County © 2005 Dick Bartlett
Adult, Los Angeles County © Todd Battey
Tadpole © 1998 Ron Altig

Habitat
Habitat, San Diego County
Habitat, San Diego County
Habitat, Los Angeles County
© Todd Battey

 
Habitat, Los Angeles County
Habitat, Orange County
 
Description
Size
Adults are 2 - 5 5/8 inches long from snout to vent (5.1 - 14.3 cm).
Appearance
A smooth-skinned frog with a flattened body and a small head with a blunt snout and small upturned eyes with no lids. Olive to brown above, with dark markings. Whitish below, sometimes spotted. No tongue. Forefeet are unwebbed. Hind feet are fully webbed with sharp black claws on the inner toes. Tadpole is translucent with tentacles at the mouth corners and a slender tail ending in a filament.
Voice  (Listen)
A 2-part trill, about 1/2 second, repeated up to 100 times per minute. Males have no vocal sacs and call from underwater during the day and at night. Calls are only faintly heard in the air.
Behavior
Totally aquatic, but will move over land on rainy nights and at night when their water source dries up, sometimes in mass migrations. Able to tolerate brackish habitats. Cannot tolerate loss of water or sustained travel over dry land. When pond water evaporates, frogs make and stay in shallow pits in the mud where the water temperature remains cooler than the surface temperature. In Africa, frogs burrow deep into the mud that remains when a seasonal pond dries up, where they can survive for at least 8 months without food.

When not feeding, frogs rest on the bottom or on rocks. Has been observed tolerating a wide range of conditions, including 40 percent seawater, freezing water, hot desert conditions, long periods without food, and estivating without water.

Releases slippery mucous secretions from the skin to repulse predators.

Adults live up to 16 years.
Diet and Eating
Feeds on anything it can catch; aquatic invertebrates, fish, amphibians, including its own larvae and recent metamorphs. A very formidable predator. Finds prey by scent, and uses its toothed jaws to hold the prey while shredding it with its rear claws and pushing it into the mouth with its forearms. This allows a frog to eat prey that is too large to swallow whole, and to scavenge. Tadpoles swim head down, vibrating the tail filament to stir up food, including algae, diatoms, protozoans, and bacteria.
Reproduction and Young
Reproduction is aquatic. Fertilization is external. In California, breeds any time from January to November with a peak in April and May. In Africa, frogs are known to migrate to newly-filled rain pools to breed, but this has not been observed in US Populations.
Females mature quickly - about 6 months after metamorphosis. A female lays several hundred to thousands of eggs, depositing them singly or in small groups on vegetation and rocks. Females can produce multiple clutches each season. Eggs hatch in 2 to 3 days.
Tadpoles congregate in pools, often schooling and feeding in the middle of deeper water to avoid predation by fish. Transformation time in the wild is not known, but tadpoles transform in 10 - 12 weeks in captivity.
Range
Originally native to South Africa. Brought to the US in the 1940's and widely used as a standard amphibian for laboratory study and human pregnancy testing in the 1940's and 1950's. A popular aquarium pet, now banned in several states including California. Released or escaped laboratory animals and pets were introduced into California mostly before the species was banned in California in the 1960s.

First found established in the wild in California in 1968. It has become established in California primarily in San Diego, Orange, and Los Angeles counties, but has also been found elsewhere, including San Bernardino, Santa Barbara, Riverside, Imperial, Kern, Ventura, and Yolo Counties, and recently in a small pond in San Francisco's Golden Gate Park.
Habitat
In California, inhabits a variety of aquatic habitats, many of which have been disturbed or made by humans standing water, including slow streams and drains, marshes, ponds, drainage ditches, flood channels, cattle tanks, sewage plant ponds, and golf course ponds. The highest densities of this species are found in permanent well-vegetated waters with soft substrates that do not freeze. Inhabits waters in arid and semi-arid regions in its native South Africa.
Conservation Issues  (Conservation Status)
Established and spreading. Most suitable freshwater aquatic habitats in California are at risk of colonization, especially with continued human-aided introductions. A threat to native amphibians and fishes, including several endangered species. Importation and possession of this frog is prohibited in California. Still a popular pet frog in some states, but banned in several others. Eradication efforts by using poisons, draining ponds, and collecting and removing frogs, are not usually successful at removing all frogs or preventing frogs from nearby areas to re-colonize the water source.
Taxonomy
Family Pipidae Tongueless Frogs
Genus Xenopus Clawed Frogs
Species laevis African Clawed Frog

Original Description
Not available

Meaning of the Scientific Name
Not available

Alternate Names
None

Related or Similar California Frogs
None in California.

More Information and References
Natureserve Explorer

California Dept. of Fish and Game

AmphibiaWeb


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.


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.

This frog is not included on the Special Animals List, meaning there are no significant conservation concerns for it in California according to the California Department of Fish and Game.


Organization
Status Listing
U.S. Endangered Species Act (ESA)
California Endangered Species Act (CESA)
California Department of Fish and Game
Bureau of Land Management
USDA Forest Service
Natureserve Global Conservation Status Ranks
World Conservation Union - IUCN Red List




 


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