The eastern hellbender, Cryptobranchus alleganiensis, is a species of the aquatic giant salamander native to the eastern and central United States. It is the only extant member of the genus Cryptobranchus, and other closely related salamanders in the same family are in the genus Andrias. Their means of respiration is unique, as it involves cutaneous gas exchange through capillaries found in its dorsoventral skin folds. It is classified as both predator and prey in its ecosystem. They are distinguishable from other native salamanders by their giant dorsoventrally flattened body with thick folds down the sides, a single open gill slit on each sides, and hind feet with five toes each.