Ohio Frog and Toad Calling Survey

American Bullfrog

(Rana catesbeiana)

Distribution of the American Bullfrog in Ohio.

An adult American Bullfrog.

Species Description:   The Bullfrog's snout-vent length ranges from 9 to 15 cm (3.5 to 6 inches).  Its back and sides are some shade of green or brown and occasionally there are some darker blotches or spots on the back.  The belly is off-white and the chest is mottled with gray.  The skin is smooth and slimy.  There are no dorsolateral folds along the frog's back.  Instead, a ridge on each side of the head curves around the tympanic membrane from behind the eye.  The webbing on the back feet is extensive and almost reaches the tips of each toe.  The single vocal sac is internal.  When calling the throat swells, but the vocal sac is not visible.   
Habitat: Any permanent body of water is likely to be inhabited by Bullfrogs.  
Reproductive Activity: Breeding begins in late May and continues throughout the summer.  The call is a loud, guttural, three syllable “jug-o-rum” repeated two or three times in succession.    
Ohio Distribution: Walker (1946) reported that records for Bullfrogs were lacking from the northwestern section of the state but that it probably occurred locally throughout Ohio.  Sufficient field efforts would probably show that this species occurs in every county and township.  
Status: Walker (1946) suggested that humans had extirpated the species in some areas.  Today this species is so abundant that it might be partially responsible for the decline of other species.  There is no evidence that it has been extirpated, even at the local level.
Photographic Recommendations: A close dorsal view should show the lack of dorsolateral folds.  A side view should show the ridge wrapping around the tympanic membrane. 

Last modified:
Saturday, March 26, 2005

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