The green frog is a primarily nocturnal amphibian, but may sometimes be active during the day (4). As in other frogs, the green frog has fairly well developed senses (2) (4), with highly sensitive hearing (2) and bulging eyes that give a wide range of vision, aiding in the capture of prey (4).
Like most frogs, the green frog is an opportunistic feeder (8). It is a ‘sit-and-wait’ predator, and takes any prey species that is small enough to swallow (8), including insects, worms, molluscs, crustaceans, small fish and even other frogs, as well as plant material and shed animal skins (2) (4) (8). Green frog tadpoles are feed almost continuously (9), eating mainly algae (2) (9), although they will also occasionally feed on fungi and other organisms (8).
During the non-breeding season the green frog is mostly solitary (4). During the breeding season male green frogs become territorial (2) (4) (8), and will defend their territories against other males using vocalisations, posturing and physical combat (4) (8). The male green frog will set up a territory in the shallow water of a lake, pond, ditch or stream (2), and will usually live there for between one and seven weeks (8).
The green frog generally breeds between April and July (2) (4) (7) (8), although the exact timing of breeding depends on the location and in some areas may extend into late summer (8). The female lays around 3,000 to 4,000 eggs (2) in shallow, slow-flowing water (1) (4) (8), usually among emergent vegetation (4) (8). The eggs of multiple females will often coalesce into a single floating mass on the water’s surface (4) (8).
The eggs of the green frog usually hatch into tadpoles after three to seven days (2) (4). Larval green frogs may take anywhere between 3 and 22 months to metamorphose into the adult form, with most populations overwintering as tadpoles before metamorphosing the following summer (2) (4) (8). During metamorphosis, the tadpole develops its hind legs first, before absorbing its tail, losing its gills and forming lungs and other internal organs (4).