Range in California: Green
Northern Red-legged Frog: Red
Click here to see a range map of the former Rana aurora subspecies.
Listen to this frog:
A short example
More sounds of
Rana draytonii
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Adult male, interior of the Coast Range, western Fresno County |
Juvenile, Contra Costa County |
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Adult, San Mateo County |
Adult, San Mateo County |
Adult, San Mateo County |
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Adult, Monterey County
© Anonymous Contributor
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These frogs, discovered by Sean Barry in Butte County in 1997, are some of the last known California Red-legged Frogs remaining in the Sierra Nevada mountains.
© Sean Barry |
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Egg masses in breeding pond, shortly after hatching, Monterey County. Courtesy of David Keegan & Susan Whitford of the Santa Lucia Conservancy. |
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Tadpole, Monterey County
© 2004 William Leonard
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Habitat, coastal lagoon, Marin County |
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Habitat, cattle pond, Contra
Costa County
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Habitat, Riverside County |
Habitat, pond, San Mateo County |
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Habitat, pond, Contra Costa County
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Habitat, breeding pond, Santa Lucia Preserve, Monterey County. Courtesy of David Keegan & Susan Whitford |
Habitat, breeding pond, Santa Lucia Preserve, Monterey County. Courtesy of David Keegan & Susan Whitford
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Description |
| Size |
| 1 3/4 - 5 1/4 inches ( 4.4 - 13.3 cm.) |
| Appearance |
Coloring is reddish -brown or brown, gray, or olive, with small black flecks and spots on the back and sides and dark banding on the legs. Dark blotches on the back, typically have light coloring in the center. There is a dark mask on the head and a stripe extending from the shoulder to the front of the upper jaw. The eyes are outward oriented. The hind legs are red underneath, giving this frog its name. On older frogs the red coloring extends onto the belly and sides. The chest and throat are creamy and marbled with dark gray. Yellowish-green and black coloring mottles the groin. Toes are not completely webbed. Legs are relatively long. Dorsolateral folds are prominent.
Tadpoles are brown marked with small dark spots with eyes set in from the margin of the head. Creamy white coloring flecked with small spots covers the lower body. Eyes are set in from the margin of the head. Compare with P. regilla. |
| Voice (Listen) |
| The call is a weak series of 5 - 7 notes, sounding like uh-uh-uh-uh-uh, lasting 1 - 3 seconds. After the series there is sometimes a last note which is similar to a growl or groan. The calls are made during the day or at night in the air or underwater and are easily missed. Calls last only one to two weeks at a location. Rana draytonii south of San Francisco have paired vocal sacs. Frogs north to Del Norte County, including Rana aurora, have rudimentary vocal sacs. |
| Behavior |
| Typically a pond frog, found in or near water, but can be highly terrestrial, sometimes found in damp places far from water. Primarily diurnal. Will quickly leap off into the brush when startled. |
| Diet |
| Diet consists of 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 in permanent bodies of water from late November to April, depending on the location, and lasts for only a week or two. Fertilization is external. Amplexus is pectoral. Males develop enlarged forearms and a dark nuptial pad on each thumb. Females lay 750 - 1,300 eggs in a large gelationous cluster which is attached to vegetation beneath the water. The egg mass will eventually float to the surface. Eggs hatch after about four weeks. Tadpoles metamorphose in four to five months. |
| Range |
Endemic to California and northern Baja California. Ranges along the coast from Mendocino County in northern California south to northern Baja California, and inland through the northern Sacramento Valley into the foothills of the Sierra Nevada mountains, south to Tulare county, and possibly Kern county.
A narrow range overlap with Rana aurora occurs in Mendocino County: Shaffer et. al. in research for their 2004 paper found only Rana aurora north of Big River, Mendocino County, both Rana aurora and Rana draytonii between Big River and Mills Creek, Mendocino County, and only Rana draytonii south of Mills Creek. |
| Habitat |
| Found in humid forests, woodlands, grasslands, and streamsides with plant cover. Most common in lowlands or foothills. Frequently found in woods adjacent to streams. Breeding habitat is in permanent water sources; lakes, ponds, reservoirs, slow streams, marshes, bogs, and swamps. From sea level to 8,000 ft. (2,440 m.) |
| Taxonomic Notes |
Schaeffer et al. in a 2004 genetics study determined that R. aurora actually consists of two species, R. aurora, and R. draytonii, whose ranges overlap only in a narrow zone in Mendocino County. R. aurora is found to be closely related to R. cascadae. Other studies, including an analysis of vocal sacs, have supported separate species status, concluding that R. aurora and R. draytonii are biologically quite different.
Before being split into two species, two subspecies of Rana aurora were recognized: R. a. aurora, and R. a. draytonii. Frogs in the very large area between Del Norte County and the Walker Creek drainage in Marin County were considered to be intergrades. |
| Conservation Issues (Conservation Status) |
| Populations in the Sierra Nevada mountains and in southern California have declined seriously possibly due to introductions of non-native predators such as bullfrogs and fish, pollutants, and habitat loss due to development. As of 2004, only six recently-discovered populations are known in the Sierra Nevadas, and only a single population on the Santa Rosa Plateau in Riverside County is known from Southern Calfornia, although this frog still persists in northern Baja California. |
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Taxonomy |
| Family |
Ranidae |
True Frogs |
| Genus |
Rana |
True Frogs |
| Species |
draytonii |
California Red-legged Frog
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Original Description |
Rana aurora - 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
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Meaning of the Scientific Name |
Rana - Frog - "Rana" probably mimics how the Romans heard their call.
aurora - Latin - dawn, red - referring to the red color of the underside of the hind legs.
draytonii - honors Drayton, Joseph
from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz
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Alternate Names |
Formerly Rana aurora draytonii - California Red-legged Frog
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Related or Similar California Frogs |
Rana aurora
Rana boylii
Rana catesbeiana
Rana cascadae
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More Information and References |
Natureserve Explorer
California Dept. of Fish and Game
AmphibiaWeb
Center for Biological Diversity
Shaffer, H. Bradley, G. M. Fellers, S. Randal Voss, J. C. Olive and Gregory B. Pauly (2004 Species boundaries, phylogeography and conservation genetics of the red-legged frog (Rana aurora/draytonii) complex. Molecular Ecology 13(9): 2667-2677)
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.
Davidson, Carlos. Booklet to the CD Frog and Toad Calls of the Pacific Coast - Vanishing Voices. Cornell Laboratory of Ornithology, 1995.
Jones, Lawrence L. C. , William P. Leonard, Deanna H. Olson, editors. Amphibians of the Pacific Northwest. Seattle Audubon Society, 2005.
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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 referred to as Rana aurora draytonii on the Special Animals List.
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Organization
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Status Listing
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| U.S. Endangered Species Act (ESA) |
FT |
Threatened |
| California Endangered Species Act (CESA) |
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| California Department of Fish and Game |
DFG:SSC |
California Species of Special Concern |
| Bureau of Land Management |
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| USDA Forest Service |
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| Natureserve Global Conservation Status Ranks |
G4 |
Apparently Secure |
World Conservation Union - IUCN Red List
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IUCN:NT |
Near Threatened |
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