Illinois Natural History Survey - University of Illinois

Anura         Rana clamitans -- Green Frog

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DuPage County, IL; photo by Mike Redmer distribution map

Purple shade indicates vouchered specimens. Light blue (cyan) shade indicates photographic records. Yellow shade indicates verified sighting. Slanted hatch indicates pre-1980 records only

NOTE: Not all specimens upon which these maps are based have been verified.

Key Characters: Well-developed fold around rear of tympanum extends middle way down the back; toes webbed about halfway to tips.

Similar Species: Bullfrog.

Subspecies: Green frog, R. c. melanota; and intergrades between the green frog and the bronze frog, R. c. clamitans.

Description: Medium-sized (5.7-9.5 cm TL) olive, brown, or green frog with dim black spots on back. Chin, breast, and undersides of legs sometimes marked with dark spots or mottling. Mature male with larger tympanum, enlarged thumbs during breeding season, stouter front legs, bright green upper jaw, and yellow throat. In southwestern counties, males tend to have dusky upper jaws and green throats.

Habitat: A variety of shallow, weedy, aquatic habitats around lakes, ponds, and streams in wooded areas. In southern counties, where rock outcrops are abundant, it often is associated with small spring-fed streams.

Natural History: Like bullfrogs and leopard frogs, startled individuals emit loud, high-pitched yelps as they jump. Breeding calls (1-3 explosive banjolike twangs) are heard from May to September. Paired vocal pouches are not evident externally. Tadpoles overwinter to transform the following summer.

Status: Abundant in northern Illinois, the Shawnee Hills, parts of eastern Illinois, and along Middle Mississippi Border Division. Absent from Grand Prairie and most of Southern Till Plain counties.


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