The American Bullfrog (Lithobates catesbeianus) is one of North America’s largest native frogs, known for its deep, booming call. This large amphibian is a conspicuous presence in ponds, lakes, and slow-moving rivers across its range. Given its size, the bullfrog is a formidable predator. This article addresses the bullfrog’s predatory habits, focusing on its diet and consumption of other amphibians.
The Direct Answer: Bullfrogs as Amphibian Predators
The direct answer to whether bullfrogs eat other frogs is yes, as they are highly opportunistic carnivores that consume virtually any animal they can overpower and fit into their mouths. This voracious appetite extends to nearly all smaller anurans, making the bullfrog a significant predator of native frog species like treefrogs and leopard frogs. In some introduced ranges, their predation on native amphibians has been linked to the decline of vulnerable species.
Bullfrogs also readily exhibit cannibalism, preying upon smaller juvenile bullfrogs and even their own tadpoles, especially when resources are limited. The limiting factor for the bullfrog’s consumption of other amphibians or reptiles is strictly the size of the potential prey. Amphibians like newts and salamanders are also included in the bullfrog’s diet if they stray too close to the large predator.
Diet Beyond Amphibians
Bullfrogs are generalist predators considered apex hunters in many of their freshwater habitats. Their diet is remarkably broad and includes a wide range of invertebrates and small vertebrates. Common non-amphibian prey includes large aquatic insects, such as dragonfly nymphs and water beetles, as well as terrestrial invertebrates like snails and worms.
Their menu frequently features crayfish and small fish within striking distance. Studies of bullfrog stomach contents have also revealed they occasionally consume small snakes, lizards, and even warm-blooded prey. This includes small mammals, such as mice, and small birds, including ducklings, demonstrating the breadth of their predatory capability.
Size, Habitat, and Hunting Style
The bullfrog’s success as a predator is directly related to its physical attributes and hunting methods. As the largest true frog in North America, adults can reach a snout-to-vent length of up to 8 inches and weigh over a pound. This substantial size provides a distinct advantage over smaller prey animals.
While bullfrogs do not have teeth for chewing, they possess small, pointed maxillary teeth along the upper jaw and vomerine teeth on the roof of the mouth. These structures function to grip and secure struggling prey before it is swallowed whole. The bullfrog’s wide mouth enables it to consume prey items that appear disproportionately large compared to the frog’s head.
Bullfrogs employ a classic “sit-and-wait” or ambush hunting strategy, often remaining motionless at the water’s edge in ponds, marshes, or slow-moving streams. They rely on their camouflage and patience, waiting for an unsuspecting creature to move within range. Once prey is detected, the bullfrog uses a powerful lunge or a rapid, sticky tongue strike to capture the meal and immediately swallow it.