Hyla regilla
(Pacific Treefrog)
also: Pseudacris regilla
(Pacific Chorus Frog)

Key Characteristics:
Adult Characteristics Tadpole Characteristics

Egg Characteristics

Dark eye stripe

Brown dorsally
and light ventrally

Small clusters
(9-70 eggs)

Pads on finger
and toe tips

Eyes extend past margin of head

Pigmented

Often "y" mark
on head

Dorsal fin less arched
than Boreal Chorus
Frog tadpoles

    .

Limited webbing
on feet

   . .

Males call

     .        .

General Description:
Pacific Treefrogs are smaller anurans reaching sizes of around 50mm (2 in.) in length. They have smooth skin that ranges in color from varying shades of green and brown to certain individuals that are nearly black, even red to chalky gray are in their possible color repertoire. The ground color is often broken with darker blotches or spots and they have a very characteristic dark line through the eye. Ventrally, Pacific Treefrogs are lightly colored and the males may have a gray or black throat pouch during breeding season. Other important features of these frogs are the toe pads found on the ends of their fingers and toes, and the limited webbing between the toes. During the breeding season, males will call to attract females. The call is the familiar "ribbit" sound often used in movies.

The tadpoles of Pacific Treefrogs are easy to identify as Hylidae, because the eyes extend beyond the margin of the head when viewed from above. They may reach lengths of up to 55mm (2.2 in.) before metamorphosis. Pacific Treefrog tadpoles have a brown or tan dorsal coloration, with a cream or white ventral color. They differ from Boreal Chorus Frog tadpoles in that the dorsal fin is lower and less arched.

Pacific Treefrog eggs are generally laid in small clumps of 10-70. The egg masses may be attached to submerged vegetation or debris, or they may be loose on the substrate. The eggs are about 1.3mm in diameter, they have two gel layers and are colored brown dorsally and yellow ventrally.

Idaho Distribution:
The Pacific Treefrog can be found across much of the western and northern portions of Idaho. From southern British Columbia to Baja California, and east to Montana, Idaho, and Nevada. The model over predicts the distribution on the map.

Habitat:
Pacific Treefrogs can be found in a variety of different habitats. They can be found in talus slopes, agricultural areas, deserts, meadows and forested areas. Typically they are near riparian areas or some other water source such as marshes, ponds or lakes. The adults will utilize ephemeral water sources to lay their eggs.

Found from sea level to over 3000 m, usually in low vegetation near water, but also in grasslands, woodlands, forests, and farmlands.

Diet:
Known to eat beetles, flies, spiders, ants, and isopods. Larvae probably eat algae, organic debris, and plant tissue.

Ecology:
Common and widespread species. Larvae are preyed upon by carnivorousclick here for definition aquatic insects, bullfrogs, garter snakes, and many birds and mammals. Individuals are inactive in cold temperatures, frequently nocturnalclick here for definition during dry periods, and terrestrial during nonbreeding season. In some waters, species is probably displaced by bullfrogs.

Reproduction:
Breeding occurs January through August. Call is well-known "ribbet." Females have been known to lay eggs in temporary waters, causing lost production. Western Oregon study found that eggs (laid in packets of about

20-80) hatched in 3-5 wk, and young became sexually mature in less than 1 yr. Males begin moving to breeding ponds in April in northern Idaho, and tadpoles gain pre-metamorphic total length of 45-55 mm in about 2.5 mo. Multiple clutches have been documented in southern California.

Conservation:

Status:

Unprotected nongame species

Global Rank:

G5

State Rank:

S5

Important State Reference:
Schaub, D.L. and J. H. Larsen. 1978. The reproductive ecology of the Pacific treefrog (Hyla regilla). Herpetologica 34:409-416.


Species description, key characteristics and original work by John Cossel Jr. © 1997
Species ecological information from Groves et al. ©1997.
Original images provided by Charles R. Peterson, Michael Dorcas and Charlotte Corkran © 1997
Design and Optimization by Ean Harker©1999, 2000.
DAI layout by Stephen Burton, and Mike Legler © 1999.