Bullfrogs vary in color from brownish to shades of green, often with spots or blotches of a darker color on the back. The belly color ranges from white to yellow, and in some individuals is marked with black spots or a vein-like pattern. The hind feet are fully webbed.
Breeding males emit a deep bass booming call, sounding like “roo-roo-room” or “jug-a-rum,” that can be heard over a distance of more than half a mile. During the long spring and summer breeding season, males aggressively defend territory, wrestling fiercely with rival males and attempting to mate with as many females as possible.
Thousands of eggs are laid during the summer. Clutch size ranges from 6,000 to more than 20,000 eggs, with larger females producing larger clutch sizes. In Maryland, tadpoles over-winter and transform into frogs during the following summer, depending on food availability and water temperature. In the southern parts of the bullfrog’s range, metamorphosis can occur in as few as 79 days, while in the colder northern areas, metamorphosis can take more than three years.
Bullfrogs will eat any animal they can capture and swallow, including worms, insects, crayfish, fish, other frogs (including other bullfrogs), snakes, small turtles, and even small mammals and birds.
This is the largest North American frog, weighing up to 1 pound and measuring up to 8 inches in length.
This highly aquatic frog prefers still, shallow water, such as around the edges of lakes and ponds, and sluggish portions of streams and rivers.
The American bullfrog’s natural range extends from Nova Scotia to central Florida, from the Atlantic coast to Wisconsin, and across the Great Plains to the Rockies.
Bullfrogs are highly esteemed for the meat on their hind legs, which is consumed in the U.S. and abroad. A desire for frog legs for human consumption has led to the deliberate introduction of the species to aquatic habitats in the western U.S., Hawaii, and numerous foreign countries.
Bullfrogs are abundant in their native habitat and play a role in insect control and energy transfer in the ecosystem. Bullfrog tadpoles consume plants and add nutrients to the aquatic ecosystem and provide food to aquatic predators. Bullfrogs consume a wide variety of prey, and are also food to a wide variety of predators.
In places like California and Arizona, where bullfrogs have been introduced by humans but do not occur naturally, bullfrog populations are skyrocketing and causing big problems for native frog species. Native populations of western frog species are in decline due to competition with bullfrogs for resources, and predation by bullfrogs. As a result, introduced bullfrogs are driving some native species of frogs toward extinction.
Bullfrogs have a wide variety of predators that feed on their eggs, tadpoles, and adult frogs. These include aquatic insects, crayfish, fish, other bullfrogs, aquatic turtles, snakes, birds, and mammals. Humans hunt these frogs for their meat (their legs, specifically).
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