The American bullfrog (Lithobates catesbeianus) is a sizable amphibian that is prevalent throughout its original haunting grounds -- which are the United States, Canada and Mexico. These solitary frogs also have been transported to other regions of the world, including Europe, South America and Asia.
Bullfrogs are the biggest frogs in the U.S., according to the Savannah River Ecology Laboratory. They generally achieve body lengths of between 3.5 and 8 inches or so. Males are significant smaller than the females of this species. These brown, light green or grayish-green creatures feed on a wide assortment of foods, including crustaceans, small rodents, young ducks, snakes, fish eggs, bugs, salamanders, worms, bats, crayfish and fish. Bullfrogs also will readily dine on members of their own species, along with other types of frogs. Although tadpoles eat mostly herbivorous diets, fully mature individuals are serious opportunistic carnivores. Bullfrogs are, for the most part, nocturnal animals, although not exclusively so. As far as habitat goes, bullfrogs usually live in dependable bodies of water -- think rivers, bogs and ponds.
Bullfrogs that reside in colder environments gravitate toward warm climate conditions. Because of this, they spend their winters in hibernation -- if the weather reaches the freezing point or colder, that is. When it comes to hibernation, bullfrogs usually set up camp in the mud. They carve out tiny underground lairs where they can rest until the temperatures come back up.
Ponds and Hibernation
Although many do, not all bullfrogs retreat to the mud to cope through the winter months. Some opt for more aquatic hibernating environments -- think the floors of ponds or pools, for example. When bullfrogs hibernate in these aquatic settings, they typically do so in the midst of debris. Although frogs are capable of breathing both via their lungs and their skin, they do so exclusively via their skin when hibernating in the water or mud.
Overwintering in Bullfrog Tadpoles
Wee tadpoles of the bullfrog species tend to overwinter during the coldest months of the year. Overwintering involves, essentially, staying active all through the season. As a result of this, they delay undergoing the metamorphosis process until the closing of the next summer. Some bullfrog tadpoles can grow to be big, and it generally takes between one and three years for metamorphosis to occur.
- Illinois Natural History Survey: Rana catesbeiana
- Michigan Department of Natural Resources: Bullfrog (Rana catesbeiana)
- University of Michigan Animal Diversity Web: Lithobates catesbeianus
- United States EPA: Bullfrogs
- Environmental Laboratory: Rana catesbeiana
- IUCN Red List of Threatened Species: Lithobates catesbeianus
- Savannah River Ecology Laboratory: Rana catesbeiana
- Washington Natural Heritage Program: American Bullfrog