The largest European frog (body length up to 15 centimetres). The colouration of the body is variable. In general, the dorsal surface is green, occasionally with dark spots and/or a faint vertebral ridge. Distinguishable from other water frogs by its larger size. Males have prominent vocal sacs at side of mouth, which appear grey when inflated, as opposed to the whitish appearance of other species.
Inhabits different types of wetland up to 1,500 metres. Distributed from Central Europe to the Urals, Asia Minor and some parts of North Africa.
A very aquatic and predatory frog. Spends most of its time near rivers or marsh banks, where it hunts. The mating period is during April and May, during which males call throughout the night. Females pod between 700-13,000 eggs in oval groups attached to water vegetation. Hibernates under the water. Feeds mainly on insects, but often on other frogs or fish, and sometimes attacks even small rodents. Captures prey with its elastic tongue.