American Bullfrog (Lithobates catesbeianus)
Order Anura, Family Ranidae, Genus Lithobates, Species L. catesbeianus
Species
American Bullfrog (Lithobates catesbeianus)
Family
Order Anura, Family Ranidae, Genus Lithobates, Species L. catesbeianus
Size
Snout-to-vent length ranges from 90 to 152 mm or more; females are typically larger than males; weighs up to 500 grams.
Conservation
IUCN Red List Status is Least Concern with a stable population trend; highly invasive outside its native range.
Description
The American Bullfrog is a large, commanding amphibian that dominates aquatic ecosystems with its booming call and voracious appetite.
Key Features
Absence of dorsolateral folds, huge round eardrums, and uniform olive-green to brown coloration.
Physical Description
Robust, stout-bodied frog with a broad head, large prominent tympanums, horizontal pupils with golden irises, powerful hind legs, and extensive webbing on the hind feet.
Skin Texture & Coloration
Smooth to slightly granular skin with varying shades of green and brown dorsally, often mottled with dark spots, and a creamy-white or yellowish venter.
Distinguishing Features
Absence of dorsolateral folds along the back, exceptionally large tympanums, and a distinct fold of skin wrapping around the tympanum.
Habitat
Found in permanent freshwater bodies including ponds, lakes, marshes, and slow-moving rivers with abundant aquatic vegetation.
Geographic Range
Native to eastern and central North America, but widely introduced across western North America, South America, Europe, and Asia.
Behavior
Primarily nocturnal and aquatic, highly territorial males, capable of powerful leaps into water when disturbed.
Diet & Feeding
Opportunistic carnivore consuming insects, fish, small rodents, birds, and other amphibians using a sticky tongue and rapid lunge.
Reproduction
Prolonged summer breeders; males establish territories and call to attract females; females lay large surface film egg masses containing up to 20,000 eggs.
Vocalizations
Deep, resonant, foghorn-like 'jug-o-rum' call that carries a long distance over water.
Life Cycle
Eggs hatch in a few days into large tadpoles that may overwinter one or two times before undergoing rapid metamorphosis.
Conservation Status
IUCN Red List Status is Least Concern with a stable population trend; highly invasive outside its native range.
Toxicity & Defense
Non-toxic to humans, relying on powerful leaps, camouflaged skin, and loud distress calls or biting when cornered.
Ecological Role
Acts as an apex predator in many freshwater microhabitats and can significantly impact native biodiversity when introduced globally.
Similar Species
Green Frog (Lithobates clamitans), which possesses prominent dorsolateral folds extending down the back.
Observation Tips
Search shorelines at night with a flashlight, listening for the distinctive deep calls during warm summer months.
Handling & Safety
Safe to handle with wet hands, but caution should be exercised to avoid injury from powerful thrashing and strong jaws.
Seasonal Activity
Active from spring through late autumn, brumating underwater in the mud during freezing winter months.
Cultural Significance
Frequently featured in literature, folklore, and culinary traditions as a source of frog legs.
Interesting Facts
Can consume prey as large as snakes, birds, and small turtles; tadpoles can remain in the larval stage for up to three years.