American Bullfrog (Lithobates catesbeianus)
Order Anura, Family Ranidae, Genus Lithobates, Species Lithobates catesbeianus
Species
American Bullfrog (Lithobates catesbeianus)
Family
Order Anura, Family Ranidae, Genus Lithobates, Species Lithobates catesbeianus
Size
Snout-to-vent length ranges from 90 to 150 mm, occasionally reaching up to 200 mm; females are typically slightly larger than males.
Conservation
IUCN Red List status is Least Concern with a stable population trend, though it is considered invasive outside its native range.
Description
The American Bullfrog is the largest frog native to North America, known for its deep, booming call and voracious appetite, serving as a prominent apex predator in many aquatic ecosystems.
Key Features
Large size, absence of dorsolateral folds, large tympanum, and deep resonant call.
Physical Description
Robust, stout body with a broad head, large prominent tympana, powerful hind legs, and fully webbed toes on the hind feet.
Skin Texture & Coloration
Smooth to slightly rough skin, varying in color from green to shades of brown with dark mottling and a cream or white belly.
Distinguishing Features
Absence of dorsolateral folds along the back, and a large tympanum that is noticeably larger than the eye in mature males.
Habitat
Found in permanent freshwater bodies including ponds, lakes, swamps, and sluggish streams with abundant aquatic vegetation.
Geographic Range
Native to eastern North America, but widely introduced across western North America, parts of South America, Europe, and Asia.
Behavior
Primarily nocturnal and solitary, highly aquatic, territorial, and makes powerful leaps into water when startled.
Diet & Feeding
Opportunistic carnivore feeding on insects, crustaceans, small fish, birds, snakes, and other frogs using a sit-and-wait ambush strategy.
Reproduction
Breeds in late spring and summer in permanent water bodies, laying large surface films of eggs containing thousands of ova.
Vocalizations
Deep, resonant, foghorn-like call ('jug-o-rum') that can carry considerable distances across water.
Life Cycle
Eggs hatch into tadpoles that can take one to three years to undergo metamorphosis into juveniles, reaching sexual maturity in two to three years.
Conservation Status
IUCN Red List status is Least Concern with a stable population trend, though it is considered invasive outside its native range.
Toxicity & Defense
Non-toxic, relies on powerful leaps into water, camouflage, and defensive screams or struggling when captured.
Ecological Role
Acts as both a top aquatic predator controlling insect and vertebrate populations and as prey for larger wading birds, mammals, and fish.
Similar Species
Green Frog (Lithobates clamitans), which possesses prominent dorsolateral folds running down the back.
Observation Tips
Best observed at night near the edges of permanent ponds or lakes using a flashlight to spot their glowing eye shine.
Handling & Safety
Safe to handle with wet hands, but caution should be exercised to avoid dropping them due to powerful leg kicks; avoid using chemical insect repellents before handling.
Seasonal Activity
Active from spring through autumn, spending the winter months in brumation buried in the mud at the bottom of ponds.
Cultural Significance
Frequently featured in literature, folklore, and popular culture, and raised commercially for frog legs in human cuisine.
Interesting Facts
Bullfrogs are notorious voracious eaters and have been known to consume almost anything that fits in their mouths, including bats, small rodents, and birds.