Bullfrogs are well-known to Ozarkers for their size, sound and taste. Bullfrogs are the largest frogs in North America and are also among the loudest. Their easily identifiable deep, sonorous croaks have been heard at distances of more than half a mile.
Species: American bullfrog
Scientific name: Lithobates catesbeianus
Claim to fame: Bullfrogs are well-known to Ozarkers for their size, sound and taste. Bullfrogs are the largest frogs in North America and are also among the loudest. Their easily identifiable deep, sonorous croaks have been heard at distances of more than half a mile. This is the time of year when those calls are common in rural Missouri wherever there are ponds because mid-June is typically when bullfrog courtship and breeding activities are at their peak. Bullfrogs are also known for the tasty meat on their legs and are considered a game animal. Missouri’s frogging season begins at sunset on June 30 and runs through October 31.
Species status: Bullfrog populations are stable across Missouri.
First discovered: British zoologist and botanist George Kearsley Shaw wrote the first scientific description of the bullfrog in 1802.
Family matters: The bullfrog is a member of the Ranidae family – the true frogs. This family contains more than 700 species spread over every continent of the world except Antarctica. Members of this species are medium- to large-sized frogs with long legs, smooth skin and well-developed webbing between the toes.
Length: An adult bullfrog’s body – snout to vent – measures three to six inches.
Weight: Up to around one pound.
Diet: Bullfrogs are opportunistic eaters and will take advantage of the most abundant prey in their given habitat. Bullfrogs generally prey on insects, small fish, crayfish, small amphibians and even some small mammals. Bullfrogs practice the “sit and wait” hunting technique. They can wait for long periods of time for prey to pass by, then quickly grab the prey with their tongues and bring it back to their mouths to eat.
Distinguishing characteristics: Bullfrogs usually range from green to olive to brownish in color. The belly is white and the hind legs are marked with distinct dark-brown bars. Adult males will show bright yellow throats during breeding season.
Life span: Seven to nine years in the wild
Habitat: Bullfrogs require a habitat with permanent water so they spend much of their lives around lakes, ponds, rivers, sloughs and permanent swamps or marshes. In winter, bullfrogs avoid cold water temperatures by burrowing into mud at the bottom of rivers or ponds. Adult bullfrogs usually enter their winter homes around the last week of October. During heavy summer rains, both young and adult bullfrogs will move overland to other bodies of water.
Life cycle: Bullfrogs breed between mid-May and early July. Males tend to be aggressive toward other males during the breeding season; often pushing, kicking, bumping or biting when an intruding male approaches a calling station. While the female lays her eggs, the male bullfrog fertilizes them. The female lays a wide floating mass of eggs on the water’s surface. Each clutch can contain up to 20,000 eggs and some females produce two clutches per summer. In four to five days, the eggs hatch and the tadpoles begin feeding on algae and growing quickly. Tadpoles usually take about 11 to 14 months to metamorphose into froglets in Missouri, but the bullfrog froglet takes an additional two to three years to reach its adult size.