American Bullfrog
Lithobates catesbeianus
Conservation Status:
State Status: Secure
Global Assessment: Least Concern
Photographed by Rebecca Gelernter
Listen to call:
Description
Bullfrogs are the largest frog in North America, reaching up to eight inches long and weighing over a pound. They can be green, brown, or yellow in color. Some may have dark banding on their backs and legs. Their underside is white, usually mottled with yellow or gray patches. This species of frog has prominent eardrums, which are located directly behind the eye. Bullfrogs have very long hind legs with large, webbed back feet. Males are larger than females and have yellow throats, while females have white throats. In females, the eardrum is roughly the same size as their eye, whereas it is larger than the eye in males.
Habitat
In Connecticut, bullfrogs can most often be
found in large permanent water bodies or man-made habitats. This includes areas such as swamps, ponds, lakes, canals, pools, and ditches. Unlike other species of frogs, Bullfrogs do not need to stay away from bodies of water occupied by fish. Due to their large size, they do not need to worry about being preyed on by fish. Tadpoles live in shallow water to avoid predators.
Behavior
Bullfrogs are very skittish, solitary creatures. They are mostly active at night, and inactive during the cold season– hibernating underwater buried in the mud. They are highly aquatic, and spend most of their time in or near a body of water. Both genders croak, and they get their name from the male’s call that sounds similar to a bull. These ambush hunters eat anything that they can fit in their mouth, including rodents,
other amphibians, crustaceans, small birds, worms, insects, bats, and fish eggs. They will lunge at their prey quickly so it has little chance of getting away. They are able to jump a distance ten times that of their body length. Tadpoles eat algae, pollen, and any other small particle they can find. Bullfrogs are very common in Connecticut due to a lack of predators. The few predators they do have are large birds, otters, and snakes. They are partially resistant to copperhead venom. Humans also hunt these frogs to eat their legs. When threatened, they will retreat to deeper water, and if they are caught, they will let out a scream. Males are territorial, and display aggression if met by another dominant male. This will usually result in them wrestling each other. In Connecticut, breeding season peaks in July. Eggs are laid in sheets that either float or are attached to substrate in the water. Clutches can be up to 20,000 eggs each.
Range
Present
American Bullfrog
Photographed by Mark Apgar
Often Confused with
Green Frog
Photographed by Alyssa Jones
The American bullfrog is visually similar to the green frog. The easiest way to tell them apart is by looking at the ridge that runs from the back of the frog's eye. In bullfrogs, this ridge wraps around the eardrum and then stops, whereas in green frogs, this ridge runs from the eye all the way down the back. Bullfrogs are generally larger.