Adults are medium-sized with lichenate gray or green dorsal coloration. They have a distinctive yellow wash to the insides of the thighs. These treefrogs have a wide range of dorsal coloration, and the same individual can be light gray one day and green the next. Blotches with dark outlines make up the dorsal patterning. Gray Treefrogs have rougher skin than Green Treefrogs (Hyla cinerea), the only other member of Hyla in Indiana. The Cope's Gray Treefrog and Eastern Gray Treefrog cannot be distinguished morphologically. Juveniles have reduced dorsal patterning and tend to be green rather than gray. Gray Treefrogs grow to be about 1.5 in snout-vent length.
Gray Treefrogs lay their eggs in small clusters attached to vegetation, and transform in mid-late summer. Tadpoles are small with heavy mottling on the tail; they often have red or orange coloration on the tail as well.
These two species (Hyla chrysoscelis and Hyla versicolor) are morphologically and ecologically identical, which is why they were given a single species page on this website. Though one species tends to be more associated with the south (H. chrysoscelis) and one with the north (H. versicolor), there is considerable range overlap and the two can sometimes be found utilizing the same wetlands or even hybridizing. Aside from genetic differences, these frogs do have distinctive vocalizations which can be used in the field to differentiate these species. Additionally, in southwestern Indiana, the Green Treefrog (Hyla cinerea) can be found in the same habitat as these species. Both of these frogs can be bright green under the right conditions, but the Green Treefrog is noticeably more slender with smoother skin and usually has distinctive lateral white stripes and some yellow spots dorsally.
The calls of these two species are the best way to tell them apart in the field. Eastern Gray Treefrogs produce a slower, melodic trill (somewhat birdlike), while that of the Cope's Gray Treefrog is faster and more abrupt. In the field, these are often difficult to distinguish unless you have an audio reference. Listen to the call courtesy of the Indiana DNR.
Ecology and Conservation
Gray Treefrogs are generalists that may be found in hardwood forests, open shrubland, and even fields and grasslands when forested areas are nearby. Though they require ephemeral wetlands for breeding, they will often utilize flooded fields and low swales that few other amphibians can breed in. These frogs deal well with human encroachment and are common both in rural and suburban areas, occasionally breeding in pools and flooded flower pots and frequenting glass windows and doors where building lights attract insects at night. This species spends a large amount of time concealed high in trees and is difficult to find outside of the breeding season. However, these frogs are active throughout the warmer parts of the year (anytime from March - October) and may be heard calling sporadically from the trees during rainy weather. These frogs feed on insects, largely arboreal species.
Gray Treefrogs breed from April through July in flooded fields, ponds, ephemeral wetlands, and swales usually after heavy rainfall. They begin calling during April in some parts of the state and continue through July further north. Breeding activity may be triggered anytime during spring or early summer when rainy, mild conditions are present.
This species is widespread and adaptable with no known major threats to its populations in Indiana.
These species are found throughout the eastern United States from Texas and northern Florida into Canada and Maine. Gray treefrogs occur throughout Indiana, with Eastern Gray Treefrogs being more prevalent in northern Indiana and the Cope's Gray Treefrogs in the southern part of the state. There is some range overlap, especially in central Indiana.
These two frogs are superficially morphologically indistinguishable, but the Eastern Gray Treefrog (Hyla versicolor) is tetraploid (i.e., has four sets of chromosomes), whereas the Cope's Gray Treefrog (H. chrysoscelis), like humans and most other animals, is diploid (i.e., has two sets of chromosomes). See the Distribution section above for a description of where these species are found in Indiana. These frogs are members of the family Hylidae, which is a globally diverse group and is represented by a total of 6-7 species in Indiana.
Is it dangerous?
Though the skin secretions of these frogs are known to be toxic, these toxins must be ingested to take effect. It is advisable to wash your hands after handling this species and to ensure that children do not put them in their mouths or their eyes.
Brodman, R. 2003. Amphibians and Reptiles from Twenty-three Counties of Indiana. Proceedings of the Indiana Academy of Science 112:43-54.
Conant, R. and J. T . Collins. 1998. Reptiles and Amphibians of Eastern and Central North America. Third Edition, Expanded. Houghton Mifflin, New York, NY.
Finkler, M. S. 2013. Hyla versicolor. Gray Treefrog. Geographic distribution. Herpetological Review 44:472.
Minton, S. A. Jr. 2001. Amphibians and Reptiles of Indiana. Indiana Academy of Science, Indianapolis, IN.
Pierson, T. 2012. Hyla versicolor. Gray Treefrog. Geographic distribution. Herpetological Review 43:299.
Timm, A. and V. Meretsky. 2011. Anuran Habitat use on Abandoned and Reclaimed Mining Areas of Southwestern Indiana. Proceedings of the Indiana Academy of Science 113:140-146.