This quietly resting canyon treefrog probably hunkered down for the day.
Although the canyon treefrog, Hyla arenicolor, is common to abundant in many areas, its habit of hunkering down and resting quietly on streamside boulders and rock faces, in rock fissures, concealed in talus, or in crevices in concrete bridges where its pallid coloration renders it almost totally camouflaged, assures that this anuran is usually overlooked.

Having a disjunct range this 2” long treefrog occurs in the Davis and Chisos Mountains of TX as well as much of NM, AZ, and UT, then locally in southwest NV and CO. Its occurence is restricted to areas where at least a small amount of water is permanently available.

As are most treefrogs, this species is capable of remarkable and rapid color and pattern changes. By night it assumes a ground color of rather dark buff, gray, or olive, and is often patterned with extensive darker lichenate markings or well separated, dark-edged, rounded or oval dark markings. The darker markings may be little more than smudges or be well defined, and may be brown, green, or of an intermediate color. Markings may be best defined and ground color the darkest when the frog is chorusing on rainy nights. The lightest colors are assumed when the frog is resting quietly in the morning sun. At such a time the ground color is most apt to be an off-white, palest olive, or very light pinkish-tan, and the dark markings barely discernible. The dorsal skin is rough. A dark-bordered light spot is nearly always discernible beneath the eye. The concealed surfaces of the hind legs are orangeish. The vocal sac is rounded. Males have a dark throat skin; that of the females is light.

When small, tadpoles are quite dark in overall coloration, but with growth lighten considerably and may even appear nearly gold just prior to metamorphosis. The tailfin is usually conspicuously spotted, at least dorsally.

The call, a repetitious stacatto of hollow-sounding notes, is heard most often immediately prior to, during, or closely following rains.