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Anura Rana catesbeiana -- Bullfrog
Purple shade indicates vouchered specimens. Light blue (cyan)
shade indicates photographic records. Yellow shade indicates verified
sighting. Slanted hatch indicates pre-1980 records only
NOTE: Not all specimens upon which these maps are based have been verified.
Key Characters: Well-developed dorsolateral folds tracing rear border of tympanum but not extending onto sides of body; toes webbed nearly to tips.
Similar Species: Green frog.
Description: Large (9-15 cm SVL) olive, green, or brown frog sometimes with dots or obscure black blotches on back. Backs of juveniles and tadpoles covered with small, evenly scattered black dots. Belly ranges from white to yellow, in some individuals marked with black spots or networks. Tympanum distinctly larger than eye. Males with single vocal pouch under lower jaw, yellow throat, larger tympanum and, during the breeding season, swollen thumbs.
Habitat: Permanent bodies of water (lakes, ponds, rivers, sluggish portions of streams) in forests, prairies, and disturbed habitats (including urban areas).
Natural History: Adult tends to be solitary. Eats any animal it can capture and swallow: arthropods, other frogs, snakes, even small mammals and birds. Bullfrogs have been introduced as food for humans in some parts of the world. Breeding male emits deep bass "jug-a-rum" breeding call. During long summer breeding season (April-August), males sometimes aggressively defend part of pond and mate with entering females. Thousands of eggs are laid in summer. Tadpoles overwinter and transform the following summer.
Status: Abundant statewide in permanent aquatic habitats.