American Bullfrog

A large, robust ranid frog typically measuring 3.5–6 inches (8.9–15.2 cm) in length, with some individuals exceeding 8 inches (20.3 cm). Body is heavy-bodied with a broad head and powerful hind limbs. Dorsal coloration is variable, typically green, olive, or brown, often with irregular darker mottling or spots. The skin is relatively smooth. A key diagnostic feature is the absence of dorsolateral folds, replaced instead by a prominent ridge that curves around the tympanum (ear). The tympanum is large and distinct, often larger than the eye in males. The head is wide with a blunt snout. Ventral surface is white to cream, sometimes with faint mottling on the throat. Commonly inhabits permanent water bodies including ponds, lakes, reservoirs, slow-moving rivers, and marshes, often with abundant vegetation. Highly aquatic and seldom far from water. Diet is highly opportunistic, consisting of insects, crustaceans, fish, amphibians, reptiles, birds, and small mammals.

Call is a deep, resonant, low-pitched “jug-o-rum” or “brum-brum-brum,” often compared to the sound of a distant motorboat. Calls are slow, rhythmic, and carry long distances, typically given from the water’s edge during warm months.

Similar species: Green Frog (Lithobates clamitans) is smaller, has dorsolateral folds extending partway down the body, and produces a shorter, banjo-like “plunk” call; Southern Leopard Frog (Lithobates sphenocephalus) has distinct spots and well-defined dorsolateral folds and produces a series of clucking calls; Pig Frog (Lithobates grylio) has a more pointed snout, lacks dorsolateral folds, and produces a deep snoring call.