Bookmark and Share

toad American Bullfrogs

Identify It >   Amphibian Section >   American Bullfrogs >

Scientific name:  Rana catesbeiana

Size:  Up to 200mm.  Females are slightly larger than the males

Distribution:  Very rare, but individuals are sometimes found.  American Bullfrogs were formerly introduced to the UK for the pet trade

Months seen:  March to October.  Hibernate underwater in winter

Life Span:  Up to 9 years

Habitat:  Shallow water in ponds, lakes, marshes, ditches and slow-moving streams

Food:  Frogs, toads, newts, fish, worms, dragonflies, small birds, snakes, small mammals and even other bullfrogs

Special features:  American Bullfrogs are usually green or khaki in colour with brown spots.  Adult bullfrogs are unlikely to be confused with any other species due to their enormous size.  Even the tadpoles can grow to 15cm in length.

The males have distinctive large, circular eardrums which are about twice the size of their eyes.  The call of the males, which sounds like a mooing cow (hence the 'bull' frog name), can be heard during the day or night.

American Bullfrogs hunt at night, and are known as "gape-limited predators".  This means they will eat anything which they can fit into their mouths.  They wait for prey to pass by, and then using their powerful hind legs they jump at it with their mouth open.

In addition to devouring native wildlife, American Bullfrogs are also linked to the spread of chytrid fungus.  For these reasons, the sale of American Bullfrogs as pets has been prohibited in the U.K.  Although rare, accidental introductions can still occur with tadpoles hidden amongst imported aquatic plants.

Related Pages

free newsletter