The mating call of the bullfrog is a sound we associate with summer.
It’s a deep, cow-like bellow.
While many frog species are referred to bullfrogs, the dominant species we have here in Kentucky is the American bullfrog (Lithobates catesbeianus), a native of eastern North America.
Its native range includes every state east of the Mississippi River, extending from the eastern Canadian Maritime Provinces to as far west as Idaho, south to Texas, southeastward to Florida, and up the Atlantic Coast.
The American bullfrog has been introduced around the world as a food source, but many countries now consider the bullfrog a nuisance, invasive species.
The species is a member of family Ranidae, and was first identified in the scientific literature by English zoologist George Kearsley Shaw in 1802.
Description
Coloration is olive-green above, sometimes with mottlings and bandings of grayish brown. Males have yellow throats, and black bands on their legs.
Females are a solid dark green.
Their eyes are prominent with brown irises and horizontal, almond-shaped pupils. The tympana (eardrums) are just behind the eyes.
Their fore legs are short and sturdy and their hind legs are long. The front toes are not webbed, but the back toes have webbing between the digits.
Males are smaller than females. Typically, bullfrogs measure about inches 6 inches and longer in length. They grow fast in the first eight months of life, typically increasing in weight from 0.18 to 6.17 ounces. Large, mature individuals can weigh up to 1.1 pounds.
The American bullfrog is the largest species of true frog in North America.
Habitat in Kentucky
American bullfrogs occur in every Kentucky county and are found close to permanent waters, including ponds, lakes, swamps, wetlands, and slow-moving sections of rivers and streams. But, they sometimes can be found in ditches and culverts.
Diet
Bullfrogs are voracious, opportunistic, ambush predators that prey on anything they can overpower and consume, including rodents, small lizards, snakes, crayfish and other amphibians, such as salamanders.
They also eat snails, worms, insects, and the eggs of fish.
Bullfrog season in Kentucky
Bullfrogs are a high-quality food source, rich in protein, omega-3 fatty acids, vitamin A, and potassium.
When their legs are skinned, white meat is revealed. Their legs have a sweet mild flavor and texture that is similar to chicken wings when grilled, fried or baked.
By regulation, the taking season for bullfrogs opens at noon on the third Friday in May, May 16 this year, and runs through Oct. 31.
Bullfrogs are typically taken with .22 rifles, recurve bows shooting fishing arrows, a pole and line, speared with a gig, or hand grabbed. If bullfrogs are taken with a rifle, a hunting license is required. If taken by pole and line, a fishing license is required. If taken with a gig or hand-grabbed, then either a hunting or fishing license is valid.
The daily noon-to-noon limit for bullfrogs is 15.
Life cycle
After selecting a male, and mating, the female deposits eggs in his territory, in shallow water among vegetation. She can lay up to 20,000 eggs. The male simultaneously releases sperm, resulting in external fertilization.
The eggs form a thin, floating sheet which may cover an area of 5.4 to 10.8 square feet. The embryos develop best at water temperatures between 75 and 86 degrees, and hatch in three to five days.
Newly hatched tadpoles show a preference for living in shallow water with fine gravel bottoms.
As they grow, they tend to move into deeper water. The tadpoles initially have three pairs of external gills and several rows of labial teeth. They pump water through their gills by movements of their mouth, trapping bacteria, single-celled algae, protozoans, and pollen grains as sustenance. As they grow, they begin to ingest larger particles.
They have downward-facing mouths, deep bodies, and tails with broad dorsal and ventral fins.
Time to metamorphosis into a frog ranges from a few months in the southern part of the range to three years in the north, where the colder water slows development.
The American bullfrog’s lifespan in the wild is believed to be about nine years, but one lived for almost 16 years in captivity.
