California Reptiles & Amphibians

Rana pretiosa - Oregon Spotted Frog

Click on a picture for a larger view

Historical Range in California: Red
Dot-locality range map

Listen to this frog:

A short example

More sounds of
Rana pretiosa

More pictures of this frog
and its habitats:

Northwest Page

Adult, Lane County, Oregon

Adult underside, Lane County, Oregon

Adult, Lane County, Oregon

Juvenile, Lane County, Oregon

View of the groin area, Lane County, Oregon

Adult, Klickitat County, Washington

Adult male, Thurston County, Washington, courtesy of Kelly McAllister, Washington Department of Fish and Wildlife

Adult male, Thurston County, Washington. © Gary Nafis. Specimen courtesy of Kelly McAllister, Washington Department of Fish and Wildlife

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

Calling adult male, Thurston County, Washington

Tadpoles, Thurston Co., WA
© 1997 William Leonard

Newly-laid eggs, Klickitat County, Washington. © Gary Nafis. Courtesy of Marc Hayes

Habitat

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

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

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

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

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.)

Voice (Listen)

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

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.
This species is fairly sluggish. To avoid danger, it typically swims a short distance and hides, or swims to the bottom to hide.

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. Fertilzation is external. (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.

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).

Range

Historically, this species ranged from extreme southwest British Columbia south through Washington and Oregon, to extreme northeast California, where it is 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.

Frogs on the east side of the Warner Mountains typically thought to be Rana pretiosa, should be Rana luteiventris. (Jennings, M.R. and M.P. Hayes. 1994a. Amphibian and reptile species of special concern in California. California Department of Fish and Game, Inland Fisheries Division, Final report, Rancho Cordova, California).

Marc Hayes also told me in a personal communication that the spotted frogs on 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.

Habitat

"The spotted frog was historically recorded only from scattered localities in the extreme northeastern part of California below 1,372 m (4,500 ft), where it was apparently restricted to large marshy areas filled by warmwater (more than 20°C [68°F]) springs." M. Jennings
In other areas, R. pretiosa inhabits aquatic environments mostly in mixed coniferous forests. 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.
From near sea level to 5,000 ft. (1,524 m.)

Taxonomic Notes

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.

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
Genus	Rana	True Frogs
Species	pretiosa	Oregon Spotted Frog
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
Alternate Names
None
Related or Similar California Frogs
Rana draytonii Rana aurora Rana boylii Rana cascadae Rana pipiens Rana catesbeiana Rana yavapaiensis Rana muscosa Rana luteiventris
More Information and References
Natureserve Explorer California Dept. of Fish and Game AmphibiaWeb Center for Bilogical Diversity 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. 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. Wright, Anna. Handbook of Frogs and Toads of the United States and Canada. Cornell University Press, 1949. 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.
Organization	Status Listing
U.S. Endangered Species Act (ESA)	FC	Candidate
California Endangered Species Act (CESA)	None
California Department of Fish and Game	DFG:SSC	California Species of Special Concern
Bureau of Land Management	None
USDA Forest Service	USFS:S	Sensitive
Natureserve Global Conservation Status Ranks	G2 S1	Imperiled
World Conservation Union - IUCN Red List	IUCN:VU	Vulnerable

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