A Guide to the Amphibians
and Reptiles of California

Oregon Spotted Frog - Rana pretiosa

Baird and Girard, 1853

Click on a picture for a larger view

Description • Taxonomy • Species Description • Scientific Name • Alt. Names • Similar Herps • References • Conservation Status

Oregon Spotted Frog California Range Map

Red: Historical range in California
(May not be present in these areas any more)

Click on the map for a topographical view

Map with California County Names

Listen to this frog:

A short example

More Sounds of
Oregon Spotted Frog

Northwest Page

I have no pictures yet of this frog from California. All pictures are of frogs found outside California.

Adult, Lane County, Oregon

Adult, Klickitat County, Washington

Adult, Lane County, Oregon

View of the groin are of an adult,
Lane County, Oregon

Adult, Deschutes County, Oregon © Marcus Rehrman

Juveniles

Juvenile, Lane County, Oregon

Reproduction, Eggs, and Tadpoles

Adult male in the breeding season, Thurston County, Washington,
courtesy of Kelly McAllister,Washington Department of Fish and Wildlife. © Gary Nafis

Breeding adult male, calling from shallow water, Thurston County, Washington

Calling adult male,
Thurston County, Washington

Newly-laid eggs,
Klickitat County, Washington.

Mature tadpoles, Lane County, Oregon © Mark Gary

Tadpoles, Thurston Co., WA
© 1997 William Leonard

Predation

Western Black-necked Gartersnake eating a Chiricahua Leopard Frog

Chris Rombough observed water striders (family Gerridae, aka water skippers, pond skaters, and jesus bugs) walking on the surface of the shallow edge of a pond in Deschutes County Oregon. The pond contained clusters of newly-hatched Oregon Spotted Frog, Rana pretiosa, tadpoles, which remained still in clusters on top of the degrading egg masses as frog egg embryos do before they disperse indivitually into the pond as developing tadpoles. In these pictures we see a water strider above the embryos capturing one of them, then two views of the strider as it begins to feed on it. © Chris Rombough

This short video shows the water strider beginning to eat the embryo then moving away from a rival water strider.
© Chris Rombough

Habitat

Possible former habitat, west side of Warner Mountains near an old museum record locality for this species.

Possible former habitat, 6500 ft.,
Warner Mountains, Modoc County

Habitat Outside of California

Habitat in breeding season,
Thurston County, Washington

Habitat, summer, 5,000 ft.,
Lane County, Oregon

Habitat during breeding season in March, 1,800 ft., Klickitat County, Washington.

Habitat, late summer,
Klickitat County, Washington

More pictures of this frog's natural habitat in Washington and Oregon can be seen on the Northwest page.

Short Video

An Oregon Spotted frog sitting in a canal in southern Washington in late August.

Description

Size

Adults are 1 3/4 - 4 inches long from snout to vent (4.4 - 10.1 cm). Females are larger, males grow up to 3 in. long (7.5 cm).

Appearance

Brown, tan, olive green, or reddish above with small to large irregular black spots on the back, sides, and legs, usually with indistinct edges and light centers. The face mask is dull or absent. There is a light jaw stripe. Reddish below, on the sides, and underneath the legs. The reddish color appears to be superficially painted on the surface (compared to Rana aurora.) The groin is faintly mottled, or unmottled and greyish. The hind legs are short. Eyes are turned slightly upward. Distinct dorsolateral folds.
Tadpoles are brown, with a light belly and grow to 1 3/4 in. long. (4.3 cm.)

Life History and Behavior

Our most aquatic native frog, rarely found more than 2 meters from surface water. At one site, adults are thought to move as much as 50 - 400 meters between their aquatic active season habitat and the overwintering habitat. Overwintering sites are channels or springs that do not freeze over completely. One recorded overwintering site is the mud bottom of a marshy lake fringe. Frogs often bury themselves in mud during winter, but may emerge on sunny days.
This species is fairly sluggish. To avoid danger, it typically swims a short distance and hides, or swims to the bottom to hide.

Voice (Listen)

A quiet series of rapid low-pitched clicks. Males call during the day while floating on the surface and underwater. Sunny, windless days are preferred.

Diet

Adults probably consume a wide variety of invertebrates, along with small vertebrates including small frogs. Frogs ambush their prey from water. Tadpoles consume algae and organic detritus.

Reproduction and Young

Reproduction is aquatic.
Fertilization is external, with the male amplexing the female and releasing sperm as the female lays her eggs.

(Very little is known about the specific habits of the California populations of R. pretiosa.) At sites in Oregon and Washington, Mating and egg-laying begins as soon as snow melts or the temperature warms up sufficiently, from February at lowland locations to late June at higher elevation locations. Males gather in shallow water and make an advertisement call to attract females. Breeding is concentrated within a 1-2 week period, though it may extend to 4 weeks. Adults apparently move to breeding sites 1-2 weeks before eggs are laid. Males are thought to be reproductively mature at at 2 years and females in their 2nd or third year. Females apparently breed each year.

Breeding takes place in warm vegetated shallow water beside ponds or streams, or in flooded meadows. If temporary pools of water are used, permanent water must be very near for post-metamorphs.

Egg masses averaging 598 - 643 eggs are laid in large communal groups, which are only partly submerged, floating to the surface as they mature. Eggs hatch into tadpoles in 18 - 30 days.

Tadpoles transform during their first summer. At one site in Canada, they metamorphosed in 110 to 130 days. Eggs at a location in Oregon hatched in 95 days. Tadpoles prefer warm shallows with thick aquatic vegetation. Newly-metamorphosed froglets are around 3/4 in. long (1.6 - 2/3 cm).

Habitat

R. pretiosa inhabits aquatic environments mostly in mixed coniferous forests, preferring large marshy areas that are filled by warm water from springs. Found near cool, quiet, permanent water sources; slow streams that meander through meadows, sluggish streams and rivers, marshes, springs, pools, edges of small lakes, and ponds.

Geographical Range

Historically, this species ranged from extreme southwest British Columbia south through Washington and Oregon, to extreme northeast California, where it was known from only a few scattered localities including Pine Creek, S. Fork Pitt River near Alturas, Warner Mtns., and the southwest side of Lower Klamath Lake.

Elevational Range

Found at elevations from near sea level to 5,000 ft. (1,524 m.)
"Its known elevational range in California extends from ca. 1000 m [3280 ft.] (Fall River Mills, Shasta County...) to ca. 1450 m [4757 ft.] (Pine Creek near New Pine Creek (town), Modoc County; J. Brode, pers. comm.)." (Jennings and Hayes 1994)

Notes on Taxonomy

Rana pretiosa luteiventris and Rana pretiosa pretiosa were both recognized as subspecies of Rana pretiosa until 1996 when they were split into two species, based on genetic differences, but not morphological differences.

Marc Hayes told me in a personal communication that the spotted frogs from the eastern side of the Warner Mountains, including a recent record from Cedarville, are Rana luteiventris, while those on the western side are Rana pretiosa, the Oregon Spotted Frog. (The Jennings and Hayes 2004 California survey was made before the species was split.) However, I still show the Cedarville location on this range map because its species has not been confirmed yet as far as I know.

Alternate and Previous Names (Synonyms)

Rana pretiosa - Oregon Spotted Frog (Stebbins 2003, Stebbins & McGinnis 2012)
Rana pretiosa - Spotted Frog (Stebbins 1954, 1966, 1985)
Rana pretiosa pretiosa - Western Spotted Frog (Western Frog, Pacific Frog, Spotted Frog) (Wright & Wright 1949)
Rana pretiosa pretiosa - Western Spotted Frog (Storer 1925)
Rana pretiosa pretiosa - Western Spotted Frog (Grinnell and Camp 1917)
Rana pretiosa (Baird & Girard 1853)

Conservation Issues (Conservation Status)

Considered extirpated in California, but undiscovered isolated populations may still remain in the Warner Mountains,
Modoc County. Only one frog has been recorded in the last 15 years; a juvenile found in Cedarville, Modoc County, and this frog could actually be the species Rana luteiventris. (Marc Hayes, personal communication).

Rana pretiosa has undergone a significant decline in the last 50 years throughout its range. Estimates suggest that they have been extirpated in 70 - 90 percent of their native range. Invasive species such as bullfrogs and non-native fishes, and habitat alteration such as the degradation of wetlands by agriculture, flood control, and urbanization, have been mentioned as possible reasons for the decline. Loss of springs may have destroyed available overwintering sites. Degradation of wetlands from agricultural and urban land use also stresses frog populations.

Taxonomy
Family	Ranidae	True Frogs	Rafinesque, 1814
Genus	Rana	True Frogs	Linnaeus, 1758
Species	pretiosa	Oregon Spotted Frog	Baird and Girard, 1853
Original Description
Baird and Girard, 1853 - Proc. Acad. Nat. Sci. Philadelphia, Vol. 6, p. 378 from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz
Meaning of the Scientific Name
Rana - Frog - "Rana" probably mimics how the Romans heard their call. pretiosa - Latin - to be prized or worth the effort - may refer to vivid adult coloration. from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz
Related or Similar California Frogs
Rana draytonii Rana aurora Rana boylii Rana cascadae Lithobates pipiens Lithobates catesbeiana Lithobates yavapaiensis Rana muscosa Rana luteiventris
More Information and References
California Department of Fish and Wildlife AmphibiaWeb Center for Bilogical Diversity Stebbins, Robert C., and McGinnis, Samuel M. Field Guide to Amphibians and Reptiles of California: Revised Edition (California Natural History Guides) University of California Press, 2012. Stebbins, Robert C. California Amphibians and Reptiles. The University of California Press, 1972. Flaxington, William C. Amphibians and Reptiles of California: Field Observations, Distribution, and Natural History. Fieldnotes Press, Anaheim, California, 2021. Samuel M. McGinnis and Robert C. Stebbins. Peterson Field Guide to Western Reptiles & Amphibians. 4th Edition. Houghton Mifflin Harcourt Publishing Company, 2018. Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003. Behler, John L., and F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992. Powell, Robert., Joseph T. Collins, and Errol D. Hooper Jr. A Key to Amphibians and Reptiles of the Continental United States and Canada. The University Press of Kansas, 1998. 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. Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Amphibians of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009. Elliott, Lang, Carl Gerhardt, and Carlos Davidson. Frogs and Toads of North America, a Comprehensive Guide to their Identification, Behavior, and Calls. Houghton Mifflin Harcourt, 2009. Lannoo, Michael (Editor). Amphibian Declines: The Conservation Status of United States Species. University of California Press, June 2005. Storer, Tracy I. A Synopsis of the Amphibia of California. University of California Press Berkeley, California 1925. Wright, Albert Hazen and Anna Wright. Handbook of Frogs and Toads of the United States and Canada. Cornell University Press, 1949. (Jennings, M.R. and M.P. Hayes. 1994. Amphibian and reptile species of special concern in California. California Department of Fish and Game, Inland Fisheries Division, Final report, Rancho Cordova, California). Davidson, Carlos. Booklet to the CD Frog and Toad Calls of the Pacific Coast - Vanishing Voices. Cornell Laboratory of Ornithology, 1995. Joseph Grinnell and Charles Lewis Camp. A Distributional List of the Amphibians and Reptiles of California. University of California Publications in Zoology Vol. 17, No. 10, pp. 127-208. July 11, 1917.

Conservation Status
The following conservation status listings for this animal are taken from the January 2024 State of California Special Animals List and the January 2024 Federally Listed Endangered and Threatened Animals of California list (unless indicated otherwise below.) Both lists are produced by multiple agencies every year, and sometimes more than once per year, so the conservation status listing information found below might not be from the most recent lists. To make sure you are seeing the most recent listings, go to this California Department of Fish and Wildlife web page where you can search for and download both lists: https://www.wildlife.ca.gov/Data/CNDDB/Plants-and-Animals. A detailed explanation of the meaning of the status listing symbols can be found at the beginning of the two lists. For quick reference, I have included them on my Special Status Information page. If no status is listed here, the animal is not included on either list. This most likely indicates that there are no serious conservation concerns for the animal. To find out more about an animal's status you can also go to the NatureServe and IUCN websites to check their rankings.
Organization	Status Listing	Notes
NatureServe Global Ranking	G2	Imperiled
NatureServe State Ranking	SH	All California sites are historical; the element has not been seen in the state for at least 20 years, but suitable habitat still exists.
U.S. Endangered Species Act (ESA)	FT	Listed as Threatened 9/29/14
California Endangered Species Act (CESA)	None
California Department of Fish and Wildlife	SSC	Species of Special Concern
Bureau of Land Management	S	Sensitive
USDA Forest Service	None
IUCN	VU	Vulnerable

Return to the Top