As the scientific name implies, gray treefrogs are variable in color owing to their ability to camouflage themselves from gray to green, depending on the substrate where they are sitting. The degree of mottling varies. They can change from nearly black to nearly white. They change color at a slower rate than a chameleon. Dead gray treefrogs and ones in unnatural surroundings are predominantly gray. The female does not call and has a white throat however, the male does call and can show a black/gray/brown throat during the breeding season. The female is usually larger than the male. They are relatively small compared to other North American frog species, typically attaining no more than 1.5 to 2 in (3.8 to 5.1 cm). Their skin has a lumpy texture to it, giving them a warty appearance. This species is virtually indistinguishable from the Cope's gray treefrog, H. chrysoscelis, the only readily noticeable difference being that Cope's Gray Treefrog has a shorter, faster call. However, the call rates of both gray treefrogs are temperature dependent and at lower temperatures Hyla chrysoscelis can have a call rate approximating that of Hyla versicolor. The difference in call can be heard, but it is best quantified by counting the number of pulses per second in their whistled trills. Hyla versicolor has a pulse rate of 16-34 pulses per second while Hyla chrysoscelis has a pulse rate of 34-60 pulses per second. Even though there is potential for overlap, because of t...Learn more about Gray Treefrog