Types of Small Frogs in Illinois

Illinois has many rivers and a mild climate, which makes it an ideal habitat for many species of frogs. Because of its size, the easiest to spot is probably the bullfrog, but there are many much smaller species that serenade the countryside with their evening calls in the springtime.

  1. Tree Frogs

    • Tree frogs are some of the more common small frogs in Illinois. The green tree frog (Hyla cinerea), which is found in the southern tip of Illinois, has a green back and white belly. It is often found resting on plants or windowsills. The common (or eastern) gray tree frog (Hyla versicolor) and Cope's gray tree frog (Hyla chrysoscelis) are both gray, with yellow areas along the inside of their back legs, though they have the ability to change to green if they are on a green background. The two species are almost identical, but the common gray tree frog has a slower call and an extra set of chromosomes.

    Chorus Frogs and Peepers

    • Chorus frogs, including the spring peepers (Pseudacris crucifer) are the other common genus of frogs in Illinois. The Illinois chorus frog (Pseudacris streckeri illinoensis) is an endangered subspecies of Strecker's chorus frog. It lives in sandy wetlands along the Mississippi and Illinois rivers. The western chorus frog (Pseudacris triseriata) is a small frog that can be found in several colors from green to reddish. The western chorus frogs are an important indicator species, and abnormalities found in their populations can indicate the presence of toxic pollution. The spring peeper is a brown chorus frog with a call that sounds like a high-pitched whistle.

    Cricket Frogs

    • Blanchard's cricket frog (Acris crepitans blanchardi), a subspecies of the northern cricket frog, is closely related to tree frogs, but unlike them it is not arboreal. This frog usually has a brown, gray or olive back with a white belly. It prefers to live in sunny areas along rivers, streams and ponds. Unlike other frog species, this type of tree frog usually survives for only one year in the wild, though in captivity, they may live up to five years.

    Wood Frogs

    • The wood frog (Rana sylvatica) is one of the smaller members of the Rana genus, which includes the much larger bullfrog. The wood frog is a brown frog that normally lives in forests and vernal wetlands. Its call resembles the quack of a duck. Wood frogs may migrate hundreds of yards over their lifespans, so in some areas, splintering of habitat is a major issue for them.