All About the American Bullfrog

Enlarge Image Image Gallery Diving in to take a swim. Larry Ulrich, LarryUlrich.com

Most folks find it difficult to like the cold-blooded members of the natural world, but frogs are an exception to that rule. Frogs (and their cousins, the toads) have endeared themselves to people who would never touch a snake or give a lizard a second glance. From fairy tales to lawn ornaments to stuffed toys, frogs are ever-present, loved by almost one and all. Perhaps the best-known frog species in North America is the American Bullfrog (Rana catesbeiana). Bullfrogs are pursued by children as pets and adults as food. They are the source of legends and folk tales, and they play an important role (not always positive) in their environment. 

Bullfrog basics

One of the most notable things about bullfrogs is their size. They are the largest frog in North America. Adults vary in size depending on where they live, but they can reach more than 8 inches long and weigh several pounds.

Bullfrog color runs from green to brown, usually with numerous dark splotches on the back. The throat of adult males is yellowish, and the belly is yellow or white. The exposed eardrums, or tympanums, are very large in bullfrogs. In males, the tympanums are larger than the eyes, while in females they are about the same size as the eyes. The eyes of adults are gold in color, and a distinct fold of skin extends from the eye around the ear. The front toes of adults lack webbing, while the toes of the hind feet are fully webbed.

Juvenile bullfrogs (actually all juvenile frogs and toads) are called tadpoles. Tadpoles have gills instead of lungs and are restricted to aquatic environments. As they mature, they develop legs and lungs, and lose their tails. The tadpoles of bullfrogs are also quite large, reaching up to as long as 6 inches before transforming into adults. Bullfrog tadpoles are dark green with black dots, orange eyes and yellow bellies.

Frogs and toads are very vocal animals, and each species has its own distinctive call, especially during mating season. The mating call of male bullfrogs is a deep “jug-a-rum” that can be heard up to a half mile away. When startled, both male and female bullfrogs emit a squeaking sound just before jumping into the water to escape. 

Home on the range

Bullfrogs will live in just about any permanent body of fresh water with sufficient food and cover. They are generally found in farm ponds, lakes, marshes, and slow moving streams and rivers. Bullfrogs like areas with abundant vegetation, such as reeds, cattails, water lilies and floating mats of algae, both along the water’s edge and in the water itself.