California Reptiles & Amphibians

Pseudacris (=Hyla) regilla - Pacific Treefrog, Pg. 1

Click on a picture for a larger view

Range in California: Red

Listen to this frog:

One short call

More sounds of
Pseudacris (=Hyla) regilla

Adult female, Kern County

Adult, San Gabriel Mountains, Los Angeles County

Adult male, San Mateo County

Adult, Humboldt County

Adult male, San Diego County

Adult, Butte County

Adult male, Humboldt County

Adult, Contra Costa County

Adult female, showing light skin under throat, Contra Costa County

Adult male, showing dark skin under throat,
Contra Costa County

Adult, San Diego County

Adult, Humboldt County

Adult, Del Norte County © Allan Barron

Recently transformed juvenile, San Mateo County

Adult, Sutter Buttes, Sutter County.
© Jackson Shedd.
Specimen courtesy of Eric Olson.

Adult, Butte County
© Jackson Shedd

Adult, Butte County
© Mela Garcia

Adult, Stanislaus County

Adult, Siskiyou Mountains, Siskiyou County

Adult, 9000 ft. Sierra Nevada Mountains, Tuolumne County

Adult, 3,500 ft.. Tehachapi Mountains, Kern County

Sub-adult, Mendocino County

Sub-adult, Monterey County
© Carla England

Adult, Nevada County © Maxine

Adult, San Diego County

Amphibians are often the first victims of environmental changes, such as chemical pollution, which can cause mutations including missing eyes and extra limbs. This juvenile Pacific Treefrog from San Mateo County has a deformed fifth leg. © Rory Doolin

Calling male, Los Angeles County

Calling male with extended throat sack, Alpine County

Adult male chorusing, Orange County © Jason Jones

Enlarged toe pads

Using the enlarged pads on their toes, Pacific Treefrogs are excellent climbers. They can even climb up glass.

Comparison of a California Treefrog (bottom) and a Pacific Treefrog (top) from the same creek in the San Gabriel Mountains, Los Angeles County

Comparison of the undersides of a California Treefrog (top) and a Pacific Treefrog (bottom) from the same creek in the San Gabriel Mountains, Los Angeles County

Two males amplexing a female, Fresno County © Julie Nelson

Eggs, Butte County

Viewed from above, the eyes extend to the outline of the head. Compare with Rana aurora - Northern Red-legged Frog
(which is similar to Rana draytonii - California Red-legged Frog).

Tadpole

Go to Page 2 to see more pictures of eggs and tadpoles.

Creekside habitat,
Stanislaus County

Habitat, riparian desert canyon, Riverside County

Habitat, 6500 ft., Warner Mountains, Modoc County

Habitat, Contra Costa County

Habitat, Monterey County

Habitat, Butte County,
© Jackson Shedd

Habitat, Mendocino County

Habitat, Humboldt County

Habitat, pond in San Diego County chaparral

Habitat, flooded roadside above Klamath River, Siskiyou County

Habitat, 4,500 ft.,
Kern County

High-altitude wet meadow habitat, 9,000 ft, Sierra Nevada mountains, Tuolumne County

Habitat, temporary pools on coastal plain, Humboldt County

Desert riparian canyon habitat,
San Bernardino County

Habitat in breeding season, 8,800 ft., Alpine County

Habitat, small creek, San Gabriel Mountains, Los Angeles County

Habitat,Tehachapi Mountains, Kern County

Habitat, creek, coastal San Diego County

More pictures of this frog and its habitat in the Northwest are available on our Northwest Herps page.

Short Video

A male treefrog calls while floating on a mountain pond during daylight.

Description

Size

Adults are 3/4 - 2 inches long from snout to vent (1.9 - 5.1 cm).

Appearance

This is probably the most commonly-encountered and heard frogs in California.

A small treefrog with large head and eyes, a slim waist, round pads on the toe tips, limited webbing between the toes, and a dark stripe through the middle of the eye, extending from the nostrils to the shoulders. Legs are long and slender. Skin is smooth and moist. Often there is a Y-shaped marking between the eyes. Coloring is variable: green, tan, brown, gray, reddish, cream. Most often green or brown. Color can quickly change from dark to light. Irregular dark markings on back and legs, vary in intensity with different color phases. Below is creamy with yellow underneath the back legs. The male's throat is darkened and wrinkled.

Tadpoles are up to 1 7/8 inches long ( 4.7 cm) blackish to dark brown and light below with a broze sheen. The intestines are not visible. Viewed from above, the eyes extend to the outline of the head.

Voice (Listen)

The advertisement call is high-pitched, loud and two parted, typically described as rib-it, or krek-ek, with the last syllable rising in inflection. Males also produce a land call, a prolonged one-note kr-r-r-ek sound much of the year, especially during rains. When closely interacting with other males of the same species, males may alsomake a slow trilling encounter call. Advertisement calls are heard during the evening and at night, and during the daytime at the peak of the breeding season.

(P. regilla is the most commonly heard frog in California, and its call is known throughout the world through its wide use as a nighttime background sound in old Hollywood movies, even those wich are set in areas well outside the range of this frog.)

Behavior

Despite the name, this frog is chiefly a ground-dweller, living among shrubs and grass near water. It can also be found high up a tree. Its large toe pads allow it to climb easily, and cling to branches, twigs, and grass. Active both day and night.

Diet

Eats a wide variety of invertebrates. Typical of most frogs, the prey is located by vision, then a large sticky tongue is used to catch the prey and bring it into the mouth to eat.

Reproduction

Mating and egg-laying occurs between November until July, depending on the location. Fertilization is external. Males call while in or next to water at night, and sometimes during daylight. Breeding locations include slow streams, permanent and seasonal ponds, reservoirs, ditches, lakes, marshes, shallow vegetated wetlands, wet meadows, even potholes and roadside ditches. Females lay small, loose, irregular clusters of 10 - 70 eggs, and attach them to sticks, stems, or grass in quiet shallow water. The eggs hatch in two to three weeks. Tadpoles metamorphose from June to late August. In summer, there are often large congregations of new metamorphs along the banks of breeding pools.

Range

This frog is found throughout California and its offshore islands, including the high mountains, except for most of the southeast deserts. It ranges farther east into Nevada, north through Idaho, Oregon, and Washington, into Canada and extreme southern Alaska, and south in scattered localities throughout Baja California.

Habitat

Found in a wide variety of habitats often far from water, including forest, woodland, chaparral, grassland, pastures, desert streams and oases, and even urban areas. From sea level to near 11,600 ft. (3,540 m.)

Taxonomic Notes

Alternately called Hyla regilla - Pacific Treefrog or Pseudacris regilla - Pacific Chorus Frog.

"We (actually the Society for the Study of Amphibians and Reptiles, the Herpetologists' League, and the American Society of Ichthyologists and Herpetologists) have decided it best to call our local loud mouths, the Pacific Treefrog, Pseudacris regilla. So, we're going to acknowledge that the species is not a treefrog, it's a chorus frog. But, we're going to concede that the vernacular doesn't have to be an accurate reflection of phylogeny and go with the traditional, well-recognized name, Pacific Treefrog."

Kelly McAllister, Washington Department of Fish and Wildlife

In Phylogeography of Pseudacris regilla (Anura: Hylidae) in western North America, with a proposal for a new taxonomic rearrangement 2006 Molecular Phylogenetics and Evolution 39: 293-304, Ernesto Recuero, Íñigo Martínez-Solano, Gabriela Parra-Olea, and Mario García-París present evidence that Pseudacris regilla as it is currently recognized is made up of 3 species, all of which occur in California.

The three species were named in a followup paper.

Recuero, Ernesto, Íñigo Martínez-Solano, Gabriela Parra-Olea, Mario García-París. Corrigendum to 'Phylogeography of Pseudacris regilla (Anura: Hylidae) in western North America, with a proposal for a new taxonomic rearrangement'. Molecular Phylogenetics and Evolution. 41(2): pp. 511.

Corrigendum to ‘‘Phylogeography of Pseudacris regilla (Anura: Hylidae) in western North America, with a proposal for a new taxonomic rearrangement’’
[Mol. Phylogenet. Evol. 39 (2006) 293–304]

These 3 species are:

Baja California Chorus Frog - Pseudacris hypochondriaca. This is the southern clade, ranging approximately from Santa Barbara south throughout Baja California, east to Bakersfield, Beatty, and southern Inyo County. This species is comprised of two subspecies, P. h. curta, and P. h. hypochondriaca, which occurs in California.

Pacific Chorus Frog - Pseudacris sierra. This is the central clade, ranging approximately from Humboldt County south to Santa Barbara, and east into the Sierras, and the Northcentral, and Northeast part of the state, including Shasta County, and into Nevada, Eastern Oregon, Idaho and Montana;

Northwest Chorus Frog - Pseudacris regilla. This is the northern clade, ranging along the north coast from approximately Humboldt County north into parts of Oregon and Washington.

Conservation Issues (Conservation Status)

None

Taxonomy
Family	Hylidae	Treefrogs
Genus	Pseudacris	Chorus Frogs
Species	regilla	Pacific Treefrog
Original Description
Hyla or Pseudacris regilla (Baird and Girard, 1852) - Proc. Acad. Nat. Sci. Philadelphia, Vol. 6, p. 174 from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz
Meaning of the Scientific Name
Pseudacris - Greek - pseudes false, deceptive and Greek - akris locust - means "false Acris" with reference to genus Acris regilla - Latin - regal, splendid - probably referring to the markings from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz
Alternate Names
Hyla regilla - Pacific Treefrog Pseudacris regilla - Pacific Chorus Frog
Related or Similar California Frogs
Pseudacris cadaverina - California Treefrog
More Information and References
Natureserve Explorer California Dept. of Fish and Game AmphibiaWeb Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003. Behler, John L., & F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992. Corkran, Charlotte & Chris Thoms. Amphibians of Oregon, Washington, and British Columbia. Lone Pine Publishing, 1996. Jones, Lawrence L. C. , William P. Leonard, Deanna H. Olson, editors. Amphibians of the Pacific Northwest. Seattle Audubon Society, 2005. Leonard et. al. Amphibians of Washington and Oregon. Seattle Audubon Society, 1993. Nussbaum, R. A., E. D. Brodie Jr., and R. M. Storm. Amphibians and Reptiles of the Pacific Northwest. Moscow, Idaho: University Press of Idaho, 1983. Davidson, Carlos. Booklet to the CD Frog and Toad Calls of the Pacific Coast - Vanishing Voices. Cornell Laboratory of Ornithology, 1995.

Conservation Status
The following status listings come from the Special Animals List which is published several times each year by the California Department of Fish and Game. This frog is not included on the Special Animals List, meaning there are no significant conservation concerns for it in California according to the Dept. of Fish and Game.
Organization	Status Listing
U.S. Endangered Species Act (ESA)
California Endangered Species Act (CESA)
California Department of Fish and Game
Bureau of Land Management
USDA Forest Service
Natureserve Global Conservation Status Ranks
World Conservation Union - IUCN Red List