According to AllAboutFrogs.org, birds are a common predator of frogs. Other animals that prey upon frogs include snakes, hedgehogs, shrews, fish and lizards. Frogs also prey upon other frogs.
AnimalsTime.com reports that frogs, which are slow-moving and practically defenseless, are ideal prey for almost every kind of predator. Some predatory invertebrates, such as caddisfly larvae, wasps, crickets and flatworms, are known to eat tadpoles and frog eggs. Despite its noted susceptibility to predation, the frog's primary enemy is pollution, a factor to which they have difficulty adapting. This fact is important, because frogs are considered a key factor in measuring the health of our environment.