Gray Treefrog
Hyla versicolor x chrysoscelis


photo by Jeff Humphries

Listen to the frog of H. chrysoscelis
Listen to the call of H. versicolor

Species DescriptionGray treefrogs are West Virginia's largest treefrogs, attaining snout-vent lengths of up to 2.3 inches (5.8 cm).  They have very large toe discs and the hind toes are fully webbed.  They can be gray, brown, or green and have a roughly star-shaped dark blotch on their back.  The belly is light colored and the inner thighs are orange.  There is a white spot below the eye.

HabitatThis species is usually found in open woodlands, though they are oftentimes found in urban areas -- they sometimes breed in swimming pools.  They spend almost their entire life in trees and shrubs, only descending to the ground during the breeding season.  Gray treefrogs are almost impossible to find without hearing their calls because they are camouflaged so well.

Breeding ActivityIn West Virginia, gray treefrogs begin calling around mid-April in the lower elevations and not until May in the higher areas.  The breeding season may extend through July.  In 1999, a large breeding aggregation was observed in early September near Huntington.  These treefrogs breed in any standing water source -- tire ruts, vernal pools, ponds, impoundments, swimming pools.  Females lay eggs in a thin surface film, totaling up to 1,800 eggs.  She usually lays many small masses of 30 to 40 eggs each.  Hatching occurs in 4 to 5 days and the tadpoles transform into froglets after about 60 days.

Range The gray treefrog occurs in West Virginia as two sibling species which are superficially identical.  During the breeding season, the two species can be identified by their different calling rates.  Hyla chrysoscelis has a high-pitched buzzing trill with 34-69 pulses per second (depending on the temperature) and Hyla versicolor has a trill rate of 17-35 pulses per second.  The chromosome numbers of each species is also different.  H. chrysoscelis is diploid while H. versicolor is tetraploid.  Finally, the red blood cells of H. versicolor are larger than those of H. chrysoscelis.

Dr. Michael Little completed a study on the range of the two species in WV.  Hyla chrysoscelis occurs west of the Mountains and Hyla versicolor occurs in the eastern panhandle.  Both species occur together in the ridge and valley province and throughout the mountains.

StatusNot listed.  This species seems to adapt well to some human impacts on the environment.