Cope's Gray Treefrog (Hyla chrysoscelis)*
Gray Treefrog (Hyla versicolor)*
*The Gray Treefrog and Cope’s Gray Treefrog are identical in physical characteristics, habitat, and behavior. The two species can be distinguished by their range, but even more so by differences in their call structure, which are dictated by chromosomal variations. The tetraploid Gray Treefrog is related to the diploid Cope’s Gray Treefrog and is thought to have evolved through multiple hybridization events with different diploid ancestors. Gray Treefrogs have double the chromosomes and a slower trill while the Cope’s Gray trill is much faster.
Description and Morphological Characteristics
Cope’s/Gray Treefrogs are relatively small frogs, ranging 1-2 inches in length. Their skin is less smooth when compared to other treefrogs and is covered with small warts. They are olive-green, gray, or brownish in color and most have multiple large, dark-colored blotches on their back, often resembling an irregular shaped cross. There is usually a light spot between the upper lip and eye, and the hindlegs are lined with dark bars. The belly is light colored and the hidden surfaces of the hindlegs are bright yellow-orange. They have long toes with large toepads and are skilled at both jumping and climbing.
Range
The native range of the Cope’s Gray Treefrog extends from southern New Jersey, south to northwest Florida, and west to central Texas. They can be found as far north as Canada on the western edge of the range. Gray Treefrogs share a similar range but are notably absent from the entire Gulf Coast Region where Cope’s Gray is found, aside from a small portion in southeast Texas. They are found further north and inhabit all of the northeastern states, as well as more Canadian provinces.
Habitat and Feeding
These frogs are most often found in wooded areas that exist along creeks and rivers, and where trees and shrubs overhang or grow in the water. In urban areas, they can be found on fences, posts, and around moist woody debris. They are primarily nocturnal and spend most of their lives in trees or shrubs near water, descending only to breed. Cope’s/Gray Treefrogs primarily feed on insects that can be found in the trees such as caterpillars, beetles, flies, crickets, and other small invertebrates.
Breeding and Reproduction
Breeding is triggered by day length and temperature and occurs from March to August. Males form large choruses and congregate among shrubs and the lower portions of trees at the edges of water. In the field, it is difficult to distinguish which frog is calling, unless they are both calling on the same night. In a laboratory setting using audio analysis software, the trill rates are easily seen and heard in the structure of the call. Gray Treefrogs are characterized by slower, more melodic trills, which rarely exceed more than 34 per second. Cope’s Gray Treefrogs have a harsher faster trill, easily exceeding 50 trills per second and have nearly double the note repetition rate. The females lay the eggs on the surface of shallow ponds or swamps, which attach to floating vegetation. Tadpoles hatch in 4-5 days and metamorphose within two months.
Conservation
Cope’s/Gray Treefrogs are common and abundant throughout their native ranges. They are not federally protected at this time but both species are included on the Texas Parks and Wildlife Black List.
Pertinent References
Cline, G. R. 2005. Cope’s Gray Treefrog. Pp. 449-452 in M. Lannoo (Ed.), Amphibian Declines: The Conservation Status of United States Species. University of California Press, USA.
Holloway, A., Cannatella, D., Gerhardt, H., Hillis, D. 2006. Polyploids with Different Origins and Ancestors Form a Single Sexual Polyploid Species. The American Naturalist, 167:E88-E101.
Ptacek, M. 1996. Interspecific Similarity in Life-History Traits in Sympatric Populations of Gray Treefrogs, Hyla chrysoscelis and Hyla versicolor. Herpetologica, 52(3):323-332.
Saenz, D., Fitzgerald, L.A., Baum, K.A., and Conner, R.N. 2006. Abiotic Correlates of Anuran Calling Phenology: The Importance of Rain, Temperature, and Season. Herpetological Monographs 20:64-82.
Account Author: Hailey Hester
Photos: James Childress
Edited by Christopher Schalk
Description and Morphological Characteristics
Cope’s/Gray Treefrogs are relatively small frogs, ranging 1-2 inches in length. Their skin is less smooth when compared to other treefrogs and is covered with small warts. They are olive-green, gray, or brownish in color and most have multiple large, dark-colored blotches on their back, often resembling an irregular shaped cross. There is usually a light spot between the upper lip and eye, and the hindlegs are lined with dark bars. The belly is light colored and the hidden surfaces of the hindlegs are bright yellow-orange. They have long toes with large toepads and are skilled at both jumping and climbing.
Range
The native range of the Cope’s Gray Treefrog extends from southern New Jersey, south to northwest Florida, and west to central Texas. They can be found as far north as Canada on the western edge of the range. Gray Treefrogs share a similar range but are notably absent from the entire Gulf Coast Region where Cope’s Gray is found, aside from a small portion in southeast Texas. They are found further north and inhabit all of the northeastern states, as well as more Canadian provinces.
Habitat and Feeding
These frogs are most often found in wooded areas that exist along creeks and rivers, and where trees and shrubs overhang or grow in the water. In urban areas, they can be found on fences, posts, and around moist woody debris. They are primarily nocturnal and spend most of their lives in trees or shrubs near water, descending only to breed. Cope’s/Gray Treefrogs primarily feed on insects that can be found in the trees such as caterpillars, beetles, flies, crickets, and other small invertebrates.
Breeding and Reproduction
Breeding is triggered by day length and temperature and occurs from March to August. Males form large choruses and congregate among shrubs and the lower portions of trees at the edges of water. In the field, it is difficult to distinguish which frog is calling, unless they are both calling on the same night. In a laboratory setting using audio analysis software, the trill rates are easily seen and heard in the structure of the call. Gray Treefrogs are characterized by slower, more melodic trills, which rarely exceed more than 34 per second. Cope’s Gray Treefrogs have a harsher faster trill, easily exceeding 50 trills per second and have nearly double the note repetition rate. The females lay the eggs on the surface of shallow ponds or swamps, which attach to floating vegetation. Tadpoles hatch in 4-5 days and metamorphose within two months.
Conservation
Cope’s/Gray Treefrogs are common and abundant throughout their native ranges. They are not federally protected at this time but both species are included on the Texas Parks and Wildlife Black List.
Pertinent References
Cline, G. R. 2005. Cope’s Gray Treefrog. Pp. 449-452 in M. Lannoo (Ed.), Amphibian Declines: The Conservation Status of United States Species. University of California Press, USA.
Holloway, A., Cannatella, D., Gerhardt, H., Hillis, D. 2006. Polyploids with Different Origins and Ancestors Form a Single Sexual Polyploid Species. The American Naturalist, 167:E88-E101.
Ptacek, M. 1996. Interspecific Similarity in Life-History Traits in Sympatric Populations of Gray Treefrogs, Hyla chrysoscelis and Hyla versicolor. Herpetologica, 52(3):323-332.
Saenz, D., Fitzgerald, L.A., Baum, K.A., and Conner, R.N. 2006. Abiotic Correlates of Anuran Calling Phenology: The Importance of Rain, Temperature, and Season. Herpetological Monographs 20:64-82.
Account Author: Hailey Hester
Photos: James Childress
Edited by Christopher Schalk
