The Illinois chorus frog averages one to one and one-half inches in length. It has stout forelimbs. A dark, masklike stripe is present from the snout to the shoulder. The upper jaw is light with a dark spot under each eye. A dark V- or Y-shaped marking is present between the eyes. The body is brown or olive.
The Illinois chorus frog may be found in the west central, southwestern and extreme southern portions of Illinois. This frog lives in sand prairies and sandy floodplains. Unlike toads, the Illinois chorus frog digs with its forelimbs. It burrows head first into the sand. This frog is terrestrial but is seldom seen above ground except during the breeding season. Breeding occurs February through April. The male’s call is a series of short, loud, birdlike whistles. The female deposits about 200 to 400 eggs. Transformation to the adult form occurs from May through June. The Illinois chorus frog eats small arthropods (spiders, insects, mites and others).