Gray tree frog
|Gray tree frog|
|Gray tree frog, Hyla versicolor|
It is sometimes referred to as the eastern gray tree frog, common gray tree frog, or tetraploid gray tree frog to distinguish it from its more southern, genetically disparate relative, the Cope's gray tree frog (Hyla chrysoscelis). It may sometimes be referred to as the North American tree frog by Europeans to distinguish it from their European tree frog (Hyla arborea).
Physical description 
As the scientific name implies, gray tree frogs 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 tree frogs and ones in unnatural surroundings are predominantly gray. 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. They are virtually indistinguishable from the Cope's gray tree frog, H. chrysoscelis, the only readily noticeable difference being their calls. Cope's gray tree frog has a shorter, faster call. The gray tree frog also has an extra set of chromosomes (4N), or 48 in total, and is called tetraploid gray tree frog in scientific circles. The more southerly Cope's gray tree frog, or diploid gray tree frog, retained its 2N (24) original chromosome set, so hybridization between these species would not be successful.
Both H. chrysoscelis and H. versicolor have bright-yellow patches on their hind legs, which distinguishes them from other tree frogs, such as H. avivoca. The bright patches are normally only visible while the frog is jumping. Both species of gray tree frogs are slightly sexually dimorphic. Males have black or gray throats, while the throats of the females are lighter.
Tadpoles have rounded bodies (as opposed to the more elongated bodies of stream species) with high, wide tails that can be colored red if predators are in the system. Metamorphosis can occur as quickly as two months with optimal conditions. At metamorphosis, the new froglets will almost always turn green for a day or two before changing to the more common gray. Young frogs will also sometimes maintain a light green color and turn gray or darker green after reaching adulthood.
Gender identification 
The female does not croak and has a white throat. The male does croak and has a black/gray throat. And, the female is usually larger than the male.
Mating calls and chorusing are most frequent at night, but individuals often call during daytime in response to thunder or other loud noises. Mass chorusing can be observed in some parts of their range during the spring rains.
Geographic range 
Gray tree frogs inhabit a wide range, and can be found in most of the eastern half of the United States, as far west as central Texas. They also range into Canada in the provinces of Quebec, Ontario, and Manitoba, with an isolated population in New Brunswick.
The gray tree frog is capable of surviving temperatures as low as –8°C.
The gray tree frog is most common in forested areas, as it is highly arboreal. Their calls are often heard in rural residential areas of the East Coast and the Midwest.
These frogs rarely ever descend from high treetops except for breeding. They are strictly nocturnal. Male gray tree frogs rarely have large choruses, as they are mostly solitary animals, but might vocalize competitively at the height of breeding periods.
- Hammerson (2004). Hyla versicolor. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 12 May 2006. Database entry includes a range map and justification for why this species is of least concern.
- NatureServe 'Hyla versicolor'
- Carl Gerhardt and John A. Doherty (1988). "Acoustic communication in the gray treefrog, 'Hyla versicolor': evolutionary and neurobiological implications". J. Comp. Physiol. A 162 (2): 261–278. doi:10.1007/BF00606090.
- Bernard S. Martof et al. (1980). "Amphibians and Reptiles of the Carolinas and Virginia". Chapel Hill: University of North Carolina Press. ISBN 0-8078-4252-4.
- Thomas F. Tyning (1990). A Guide to Amphibians and Reptiles. Boston: Little, Brown and Company. ISBN 0-316-81719-8.
- Quebec range map, Quebec Biodiversity website
- Adaptations of Frogs to Survive Freezing
- Herps of Texas: Gray Treefrog
- Animal Diversity Web: Hyla versicolor
|Wikimedia Commons has media related to: Hyla versicolor|
|Wikispecies has information related to: Hyla versicolor|
- Gray Treefrog - Hyla versicolor Species account from the Iowa Reptile and Amphibian Field Guide
- Gray Treefrog - Hyla versicolor - audio recording of call
- Hyla versicolor LeConte, 1825 at the Encyclopedia of Life
- Tetraploid Gray Treefrog (Hyla versicolor), Natural Resources Canada
- Northern gray tree frog New Jersey Pinelands flora,fauna,and landscapes photo galleries link to northern gray tree frog photograph