Length 1 1/4 – 2 in. (3-5 cm). [Note: Gray Treefrog and Cope's Gray Treefrog are indistinguishable by appearance.] The Gray Treefrog is the largest treefrog in the northern states. Both species live in trees and shrubs and change colors from gray-green to a light pearl- gray, depending on the background on which they rest. One of the best camouflaged of all frogs, a Gray Treefrog can blend in so well with a tree that even a careful observer has trouble spotting it. A light-colored spot on each side of the head, just beneath the eyes, does not change color. Also, look for the bright yellow coloration on the inside surface of the thighs. Well developed, sticky adhesive toe discs enable the Gray Treefrog to climb rapidly. This frog often goes through a series of frantic acrobatics trying to catch an insect several feet away. Afterwards, it may dangle by one foot until it can achieve a better balance. They spend their lives aloft, calling out from trees and shrubs, especially just before or after a summer rain. These frogs seldom come down from the trees except during breeding season when they congregate at ponds. The call of both species is a loud trill, one to three seconds in duration. The Gray Treefrog’s trill rate is slower and more melodious than the harsher trill of Cope’s Gray. While the Gray Treefrog is found throughout Ohio, Cope’s Gray Treefrog is restricted to the southern one-third of the state.
Text courtesy of the Ohio Division of Wildlife: https://wildlife.ohiodnr.gov/portals/wildlife/pdfs/publications/id%20guides/pub348.pdf