The American bullfrog averages three and one-half to six inches in length. It lacks dorsolateral folds on the back. The webbing on its feet extends to the toe tips. The body is brown, olive or green with dots or blotches. The tympanum (eardrum) is wider than the eye in males and nearly the same size as the eye in females. The vocal pouch is in the middle of the throat.
The American bullfrog may be found statewide in Illinois. It lives in lakes, rivers, marshes, ponds and creeks. The adult bullfrog is solitary and wary. It is usually found at the water’s edge. Breeding occurs from late April through August. The male’s call is “jug-o-rum” or “br-wum.” A male will defend its territory from other male bullfrogs. The female deposits about 20,000 eggs in water. Hatching occurs in less than a week. Tadpoles metamorphose (change to the land-based form) after about 14 months. Tadpoles may grow to more than six inches in length. The bullfrog eats almost any living thing that it can catch and swallow, although crustaceans and insects make up most of the diet.