The green frog averages two and one-fourth to three and one-half inches in length. Its upper lip is lighter and brighter green than the rest of the head. The belly is white. Body color can be green, bronze, olive or brown. The jaw area of males is green, and the throat is yellow. Webbing between the toes is incomplete. Distinct dorsolateral folds are present which extend about halfway along the back.
The green frog may be found in most of Illinois except the central portion. This amphibian lives in permanent streams, rivers, ponds and lakes with emergent vegetation. It is highly aquatic, rarely coming to land. The green frog swims to the bottom of a body of water to avoid predators. It is a solitary organism except when breeding. Breeding occurs throughout the summer. The male’s call is two or three well-spaced, explosive notes that resemble the plucking of a banjo string. The female deposits about 4,000 eggs in shallow surface masses on the water. Hatching occurs in a few days. Tadpoles overwinter and transform in the summer of their second season. The green frog eats arthropods (spiders, insects, mites and others), mollusks (snails, slugs and others) and annelids (earthworms, leeches) and probably any living thing it can swallow.