Gray tree frog

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Gray tree frog
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Anura
Family: Hylidae
Genus: Hyla
Species: H. versicolor
Binomial name
Hyla versicolor
LeConte, 1825

The gray tree frog or gray treefrog (Hyla versicolor) is a species of small arboreal frog native to much of the eastern United States and southeastern Canada.[2]

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[edit]

Hind leg of similar Hyla chrysoscelis

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.[3] 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 Cope's gray tree frog, or diploid gray tree frog, retained its 2N (24) original chromosome set. Hybridization between these species results in early mortality of many larvae, but some individuals survive to adulthood though they have reduced fertility.[4]

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.[5] 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.[6]

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[edit]

The female does not croak and has a white throat; however, the male does croak and has a black/gray throat. The female is usually larger than the male.

Male showing black throat

Mating[edit]

H. versicolor in amplexus
Video of gray tree frogs breeding and laying eggs

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[edit]

On flower stem

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,[7] Ontario, and Manitoba, with an isolated population in New Brunswick.

The gray tree frog is capable of surviving freezing of their internal body fluids to temperatures as low as -8°C.[8]

Habitat[edit]

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.

Behavior[edit]

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.

References[edit]

  1. ^ 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.
  2. ^ NatureServe 'Hyla versicolor'
  3. ^ 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. 
  4. ^ H. Carl Gerhardt, Margaret B. Ptacek, Louise Barnett and Kenneth G. Torke (1994). "Hybridization in the Diploid-Tetraploid Treefrogs Hyla chrysoscelis and Hyla versicolor". Copeia 1994 (1): 51–59. 
  5. ^ 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.
  6. ^ Thomas F. Tyning (1990). A Guide to Amphibians and Reptiles. Boston: Little, Brown and Company. ISBN 0-316-81719-8.
  7. ^ Quebec range map, Quebec Biodiversity website
  8. ^ Adaptations of Frogs to Survive Freezing

External links[edit]