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American Bullfrog

American Bullfrog
Lithobates catesbeianus
     =Rana catesbiana
(Order:  Anura, Family:  Ranidae)

 

Description:  The American Bullfrog is the largest frog in North America.  Its colors range from green to yellow dorsally with random mottling of darker gray.  The belly/ventral side is cream to white and may be mottled with gray. Individuals have a large external eardrum and fully webbed hind feet except for last joint of longest toe.  These frogs grow on average to be about 3.5 to 6.0 inches (9-15 cm) long in body length and their legs add another 7-10 inches (17-25 cm) to their total length.  This true frog has no dorsolateral ridges and is nocturnal.

Habitat and Range:  American Bullfrogs are mostly aquatic and prefer ponds, lakes, and slow-moving streams large enough to avoid crowding and with sufficient vegetation to provide easy cover.  They are usually found on the bank at the water’s edge. The range includes the eastern and central United States.  The species was extensively introduced in the western United States.

Diet:  Large individuals have been known to catch and swallow small birds and young snakes. Its usual diet includes insects, crayfish, other frogs, and minnows.

Video of the American Bullfrog:  "Bullfrog Hunts.... Anything!"

Link to Video:  http://www.youtube.com/watch?v=wXqK5QulbJ8&feature=fvwrel


Reproduction:  In northern areas, breeding occurs from May to July; in southern areas, February to October. The egg masses are normally attached to submerged vegetation. Tadpoles are large, olive-green in color, and may take almost 2 years to fully transform.

Species Call:  The call of the American Bullfrog sounds like a loud, low-pitched, two-part drone or bellow. The mating calls are made during the day and at night.  They are usually made by the males, but can sometimes be made by older females.

Link to calls:  http://www.californiaherps.com/frogs/pages/r.catesbeiana.sounds.html

Conservation Status:  The American Bullfrog is considered to be of the least concern in terms of endangerment.  Attempts to commercially harvest frogs’ legs have prompted many introductions of the American Bullfrog outside its natural range.


References:
Collins, Joseph T.T. 2011. Amphibians and Reptiles in Kansas: Third Edition, Revised. University of Kansas, Natural History Museum, Lawrence, Kansas.


Links:
eNature.com: http://www.enature.com/fieldguides/detail.asp?recnum=AR0026 
AllAboutFrogs.org: http://allaboutfrogs.org/info/species/bullfrog.html
ICUN Redlist of Threatened Species: http://www.iucnredlist.org/apps/redlist/details/58565/0/biblio


Image Credits:
United States Distribution Map of the American Bullfrog: USGS Northern Prairie Wildlife Research Center  http://www.npwrc.usgs.gov/resource/herps/amphibid/species/bullfrog.htm

Pictures of Lithobates catesbeiana by:  Casey Cantrell, July, 2011


Submitted by:  Casey Cantrell, July, 2011

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