American bullfrog Lithobates catesbeianus
What is an American bullfrog?
An American bullfrog is an amphibian. Amphibians are vertebrate animals (have a backbone). Their body temperature is controlled mainly by the environment and by their behavior. They spend part of their life in water and part on land, even if it’s not far from water. Amphibians have gills at some point in their life cycle. They do not have scales, feathers or fur. Their skin allows chemicals to pass through. Most amphibians undergo a life cycle with a complete change of form (egg, larva, adult). As a frog, the American bullfrog has four legs, with the hind legs larger than the front legs. The hind legs are adapted for jumping and swimming. Adult frogs have no neck or tail.
What Does It Look Like?
The American bullfrog’s skin on the upper body appears brown, olive or green with some blotches. The belly skin is white to yellow. Its feet are webbed, and the webbing extends to the tip of the toes. The tympanum (eardrum) is wider than the width of the eye. A ridge, known as a dorsolateral fold, extends from the back of each eye to just past the tympanum. Males have a single vocal pouch in the center of the throat.
How Big Is It?
The American bullfrog is three and one-half inches to six inches in length.
Where Does It Live?
Found statewide, this species lives in lakes, rivers, marshes, ponds and creeks.
How Does It Reproduce?
Breeding takes place from late April through August. The female deposits about 20,000 eggs in water as the male releases sperm on them. Fertilized eggs hatch in less than a week. The tadpoles may grow to as long as six inches. They overwinter in the water and transform to the adult form the following spring.
What Does It Eat?
The American bullfrog eats nearly anything that it can catch and swallow. Crustaceans and insects make up a good portion of the diet, but they also eat other frogs, snakes, small mammals and birds.
Does Anything Eat It?
Mammals, birds, reptiles, amphibians and fishes will eat bullfrogs. People eat them, too.
What Else Should I Know About It?
Adult bullfrogs are solitary. The male’s call is “jug-o-rum” or “br-wum.” A male bullfrog will defend its territory from other bullfrogs.
Can I Catch It?
A current sport fishing license is required to harvest bullfrogs. Methods of taking them include hook and line, gig, pitchfork, spear, bow and arrow, hand or landing net. The harvest season is June 15 to October 15. Daily harvest and possession limits apply. See https://www.ifishillinois.org/regulations/2018FishingGuide.pdf