ウシガエル
Considering the invasive nature of the "L. catesbeianus", multiple traits within the species contribute to its competitive ability. The generalist diet of the American bullfrog allows for it to consume food in different environments. When observing the contents of American bullfrog stomachs, it was discovered that adult bullfrogs regularly consume predators of bullfrog young, including dragonfly nymphs, garter snakes, and giant water bugs. Thus, the ecological check on American bullfrog juveniles in invaded areas become less effective. "L. catesbeianus" seems to exhibit traits of immunity or resistance against the antipredator defenses of other organisms. Analysis of stomach contents from bullfrog populations in New Mexico show the regular consumption of wasps, with no conditioned avoidance due to the wasps stingers. Along the Colorado river, "L. catesbeianus" stomach contents indicate the ability to withstand the discomforting spines of the stickleback fish. Reports of American bullfrogs eating scorpions and rattlesnakes also exist.