American Bullfrog

Photo Credit: Wisconsin DNR, Rori Paloski

Family: Ranidae (True frogs)
Status: Common
Size: 5.5 to 7 inches

The bullfrog can range from a dark solid olive to a lighter pale green with variable spotting. They have a distinct tympanic fold that wraps around the tympanum (ear membrane). Adult males often have bright yellow chins during the breeding season and their tympanum is twice as big as the eye. The female's tympanum is about the size of the eye.

Species range (darker) in Wisconsin

Their call is a deep resonating "jug-o-rum" that carries well. Bullfrogs are a shoreline-dependent species and are highly aquatic. Because their tadpoles do not metamorphose until at least their second year, bullfrogs require permanent water habitats like lakes. They prefer habitats with tall, undisturbed shoreline vegetation and abundant submergent and floating aquatic vegetation. Females can lay up to 20,000 eggs in large films among floating vegetation on the water's surface.