The green frog looks similar to a bullfrog but is smaller and has a ridge of skin along the sides of the back, from behind the eye to midbody, that is not found on bullfrogs. A medium-sized frog, the general color varies from green to greenish tan to brown, with the upper lip and head usually green. There may be faint dark spots on the back, and the legs usually have indistinct dark spots or bars. Adult males have a bright yellow throat. The call is an explosive “bong” that sounds like a loose banjo string.
There are two subspecies of green frogs in Missouri. Northern green frog (L. clamitans melanota), described above, and bronze frog (L. clamitans clamatans), a smaller, brownish or bronze frog with yellow lip and head, which is restricted to the southeastern part of the state.
Similar species: The American bullfrog is larger and lacks the prominent skin fold from behind the eye to midbody.