Anura Hyla versicolor- chrysoscelis -- Grey Treefrog Complex
All information found on this site falls under the INHS's Internet License Agreement.
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.
Note: A group of Illinois herpetologists is currently investigating the distributions of these two morphologically identical species. This involves surveying all 102 Illinois counties for the species and collecting males after their calls have been recorded and surface temperatures taken. This project, which has been on-going since 2000, is expected to wrap up after the 2004 field season. As soon as a manuscript has been produced and submitted for publication, the results will be released on this web site. If you have any questions concerning this schedule or would like to know more about this project, please contact the Curator.
Comment: Individuals of these two nearly identical species are distinguishable only by chromosome number (H. chrysoscelis is diploid, H. versicolor is tetraploid) and mating call (trill rate is faster in H. chrysoscelis).
Key Characters: Large toe pads; pale spot under eye; orange or golden yellow patches in groin and inner thigh.
Similar Species: Bird-voiced treefrog, green treefrog.
Description: Medium-sized (up to 6 cm SVL) brown or greenish brown frog with a black star-shaped or irregular X-shaped blotch on back. Belly pale, throat of male dark. Dark bars on arms and legs. Pustule under joint of outer finger of hand usually not divided. Recently transformed juvenile is bright green.
Habitat: Trunks and branches of trees. Adults mate in woodland pools, roadside ditches, and other temporary bodies of water.
Natural History: May change color from dark gray to light green depending on temperature and background. Diet consists of small insects and spiders. Feeding adults and juveniles are often attracted to house lights and windows where insects accumulate. Breeds late April to August. Breeding call is a guttural trill resembling Red-bellied Woodpecker song. Eggs, laid in packets attached to vegetation at water's surface, hatch in a few days and tadpoles transform in about two months. Bold red-orange and black tadpole tail provides easy identification.
Status: Common to very common throughout Illinois, but ranges of the two species remain to be distinguished.