A Guide to the Amphibians
and Reptiles of California

Cascades Frog - Rana cascadae

Slater, 1939

Click on a picture for a larger view

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

Red: Historic Range in California

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Map with California County Names

Listen to this frog:

A short example

More Sounds of
Cascades Frog

Eggs and Tadpoles

More Cascades Frogs
From the Northwest

Adult, Siskiyou County

Adult in creek, Siskiyou County

Adult, Siskiyou County

Adult under water, Siskiyou County

Adult in pond, Siskiyou County

Adult, Siskiyou County

Adult underside Siskiyou County

Adult, Siskiyou County

Adult in habitat, Siskiyou County

Adult, Siskiyou County

Adult, Trinity Alps, Trinity County
© Teejay O'Rear

Adult, found near Bear Creek east of Mt. Shasta in the southeastern corner of Siskiyou County. © Dave Biggs

Cascades Frogs from the Disjunct Southern Population - aka the Mt. Lassen Region

Adult and juvenile, Tehama County
© Natalie McNear

Adult, Shasta County © Ryan Aberg

Juveniles

Juvenile, Siskiyou County

Juvenile, King County, Washington

Unusually-pigmented Cascades Frog

This unusually yellow-orange juvenile, found at a high-elevation lake in Trinity County, appears to be missing its dark pigment, including the dark pigment normally found in the eyes. © Lauren Clark

Reproduction, Eggs and Tadpoles

Male and female in amplexus,
Kittitas County, Washington

A very cold-tolerant male frog next to melting snow in the breeding season, Kittitas County, Washington

Calling male, Pierce County, Washington

Adults in amplexus, Trinity County (captured and handled under state Scientific Collecting Permit and released at point of capture.) © Adam Clause

Egg mass, 4,000 ft.,
Clackamas County, Oregon

Tadpoles, 6,400 ft., Siskiyou County

Tadpole, King County, Washington

More pictures of eggs, tadpoles, and breeding habitat can be viewed here.

Habitat

Habitat, 6,300 ft. Siskiyou County

Habitat, 5,700 ft. Siskiyou County

Habitat, 6,100 ft. Siskiyou County

Habitat, 5,700 ft. Siskiyou County

Habitat, 5,000 ft. Tehama County

The population of Cascades frogs on Mt. Lassen has declined dramatically to the point where they may now be extinct. They were once so abundant at 8100 ft. Emerald Lake (left) that herpetologist Joseph Grinnell reported in the 1920s that there was one frog per yard around the lake. They are no longer at adjacent 8200 ft. Lake Helen either (right two pictures).

Former habitat, 5,000 ft. Tehama County

Short Videos

Cascades frogs along a creek and in ponds in Siskiyou County.

Lots of Cascades frogs filmed as they were encountered one summer morning along a creek in the mountains of Siskiyou County.

Views of several Cascades frogs in their habitat, a creek in the mountains of Siskiyou County.

A look at a Casacdes Frog breeding pond high in the Washington Cascades, including the pond surrounded by melting snow, male frogs in calling position, two calling males, and two episodes of male frogs attempting to mount other males with sounds of protest.

Several adult male frogs make calling sounds in the Washington Cascade Mountains.

An adult male frog floats on the breeding pond, trading calls with two other frogs heard in the background.

Male frogs chase each other around in the breeding pond, chattering and clucking.

The bottom frog of this pair in amplexus (probably a female) makes a few release calls as it tries to shake off the male on its back.

A male frog discovers another frog (probably a female that has already laid eggs) grabs on to her, and is carried around the pond as she tries to shake him off.

Views of some of the many egg masses in a breeding pond in the Washinton Cascades Mountains.

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

Description

Size

Adults are 1.75 - 3 inches long from snout to vent (4.4 - 7.5 cm). (Stebbins, 2003)
Females grow up to 3 inches long (7.5 cm) males up to 2.25 inches (5.8 cm.)

Appearance

A medium-sized frog with a slim waist, long legs, smooth skin, and reduced webbing on the hind feet.
Raised ridges on the sides (dorsolateral folds) are distinct.
The eyes are positioned directly laterally - they are oriented outward.

Color and Pattern

Brown, copper, tan, to olive green above, yellowish below and on the back of the legs.
Black spots with distinctly-marked edges are usually present on the back.
The sides are cream colored, and there is dark mottling on the groin.
A dark face mask is present with a light upper jaw stripe extending to the shoulder.

Larvae (Tadpoles)

Tadpoles grow to about 2 inches in length (5 cm.)
Color is dark brown, with copper to pinkish speckling, golden coloring on the sides and a finely speckled tail.

Life History and Behavior

Activity

Diurnal.
Typically found near water at higher elevations. Rarely found below 2,000 ft..
Occurs in areas covered by winter snow, hibernating throughout winter buried in mud under several feet of water or in saturated areas around ponds.
Often appears sluggish.

Defense

When frightened, a frog typically hops into water and swims away to escape, usually to the opposite shore or to the bottom where it goes head first into silt and mud.

Territoriality

Adults are not territorial, but males behave aggressively towards other males during the breeding season.

Longevity

In the Oregon Cascades, both male and females are thought to live less than 5 years, sometimes reaching 7 years (Lanoo 2005).

Recent studies not yet published (2019) show that Cascades frogs live much longer than the 5-7 years previously thought.

Voice (Listen)

A quiet series of low grating clucking noises.
Calls at night and also during the day from above and under water.

Diet and Feeding

Diet is not well known, but probably consists of a wide variety of invertebrates. Prey is located by vision, then a large sticky tongue is used to catch the prey and bring it into the mouth to eat.

Predation

Predators of adult frogs include water bugs, garter snakes, small mammals, and birds. Tadpoles and newly metamorphosed frogs are also preyed on by aquatic salamaders (Rough-skinned Newts, Northwestern Salamanders, and Long-toed Salamanders), adult Cascades Frogs, introduced salmonid fish, and even some invertebrates. (A dragonfly was observed consuming a live metamorphosing Cascades Frog in Trinity County. (Herpetological Review 38(2), 2007))

Reproduction

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

The reproductive cycle is similar to that of most North American Frogs and Toads. Mature adults come into breeding condition and the males call to advertise their fitness to competing males and to females. Males and females pair up in amplexus in the water where the female lays her eggs as the male fertilizes them externally. The eggs hatch into tadpoles which feed in the water and eventually grow four legs, lose their tails and emerge onto land where they disperse into the surrounding territory.

Adults are reproductively mature at 2 - 3 years. Females breed only once per year.
Males sit in shallow water and make a faint advertisement call to attract females.

Frogs overwinter near the breeding ponds, becoming active as the ice thaws.
Breeding begins soon after the snow begins to melt, from March to mid August depending on the location.

Breeding takes place in temporary and permanent bodies of water generally lacking fish, with silt or mud substrates, often smaller bodies of water near larger lakes. Breeding is explosive, lasting only about a week or less at a location.
Adults return to the same locatiion each year to breed.

Eggs

Eggs are laid in a mass the size of an orange or small grapefruit containing 300 -800 eggs which is not attached to vegetation, but partly submerged in shallow water. Clusters of eggs are often laid in aggregations.
Eggs are black above, and white below, and are widely spaced in the gelatinous mass.

Tadpoles and Young

Tadpoles group together in large aggregations.

Tadpoles transform in about 2 months after hatching from the eggs.
There is no doucmented evidence that tadpoles overwinter, but it is possible.

Habitat

Inhabits wet mountain areas in open coniferous forests to near timberline, including small streams, small pools in meadows, lakes, bogs, ponds, and marshy areas near streams. Typically found in water with no predatory fishes.

Geographical Range

Historically, this frog was found in fragmented populations in extreme northern California, from the edge of the northern Sierra Nevada mountains to Mt. Lassen, Mt. Shasta, the Marble Mountains, and the Trinity Alps. It is now missing from an estimated 50 percent of its former range in California, and most of its former southernmost locations, including Mt. Lassen.

Beyond California the species ranges throughout the Cascades Mountains of Oregon and Washington, in the Olympic Mountains, and barely into British Columbia, Canada.

Elevational Range

From 755 ft. (in Washington) to around 9,000 ft. (230 - 2740 m).

Notes on Taxonomy

Considered a subspecies of Rana pretiosa before 1939. No subspecies are currently recognized. Frogs in California are isolated from the main Cascades populations.

Jennings and Hayes, who have extensively surveyed California's frogs, suggested in 1994 that California Cascades Frogs should be investigated for cryptic taxa.

R. cascadae in the Lassen region are likely distinct from those in the Siskiyou-Klamath region:

Fellers et. al. (*2007) note that Monsen and Blouin (**2003) in a range-wide evaluation of the genetic diversity of Rana cascadae suggested that California R. cascadae are sufficiently distinct from populations in Oregon and Washington to warrant designation as a Distinct Population Segment and that Case (***2003) found evidence that R. cascadae in the Lassen region vary from those in the Klamath-Siskiyou region. They recommend that "a more detailed genetic evaluation [of] R. cascadae in California and southern Oregon is needed to determine the boundaries of genetic differentiation."

Alternate and Previous Names (Synonyms)

Rana cascadae - Cascades Frog (Stebbins 1966, 1985, 2003, Stebbins & McGinnis 2012)
Rana aurora cascadae (Stebbins 1954)
Rana cascadae - Slater's Frog (Slater's Spotted Frog, Cascade Frog) (Wright & Wright 1949)

Conservation Issues (Conservation Status)

Although it is still common and apparently in no trouble in Oregon and Washington, the Cascades Frog is no longer present in approximately 50 percent of its historical range in California, and has disappeared from as much as 99 percent of their southernmost California populations, including Mt. Lassen, where they were once abundant. Numbers are small in extant populations.
Introduced sport fish, solar UV-B radiation, contaminants such as airborne environmental pollution and fungal pathogens, and loss of open meadow habitat due to fire suppression, have all been suggested as factors contributing to the decline of Cascade Frogs in California.

Taxonomy
Family	Ranidae	True Frogs	Rafinesque, 1814
Genus	Rana	True Frogs	Linnaeus, 1758
Species	cascadae	Cascades Frog	Slater, 1939
Original Description
Slater, 1939 - Herpetologica, Vol. 1, p. 145 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. cascadae - of the Cascade Mountains, WA - "named from the region in which it was 1st found" from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz
Related or Similar California Frogs
LIthobates yavapaiensis LIthobates catesbeiana Rana draytonii Rana boylii Rana aurora Rana pretiosa Lithobates pipiens
More Information and References
California Department of Fish and Wildlife AmphibiaWeb 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. Davidson, Carlos. Booklet to the CD Frog and Toad Calls of the Pacific Coast - Vanishing Voices. Cornell Laboratory of Ornithology, 1995. * Fellers, Gary M., Karen L. Pope, Jonathan E. Stead, Michelle S. Koo, and Hartwell H. Welsh, Jr. Turning Population Trend Monitoring into Active Conservation: Can We Save the Cascades Frog (Rana cascadae) in the Lassen Region of California? Herpetological Conservation and Biology 3(1):28-39. Submitted: 30 May 2007; Accepted: 19 October 2007. *Monsen, K.J., and Blouin, M.S. Genetic structure in a montane ranid frog: Restricted gene flow and nuclear-mitochondrial discordance. Molecular Ecology 12:3275-3286. 2003. *Case, S.M. Biochemical systematics of members of the genus Rana native to western North America*. Systematic Zoology 27:299-311. 1978.

Conservation Status
The following conservation status listings for this animal are taken from the April 2024 State of California Special Animals List and the April 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. Check the current California Department of Fish and Wildlife sport fishing regulations to find out if this animal can be legally pursued and handled or collected with possession of a current fishing license. You can also look at the summary of the sport fishing regulations as they apply only to reptiles and amphibians that has been made for this website. ESA Note: Date of FGC vote to advance to candidacy was 20171011.
Organization	Status Listing	Notes
NatureServe Global Ranking	G3	Vulnerable
NatureServe State Ranking	S3	Vulnerable
U.S. Endangered Species Act (ESA)	None
California Endangered Species Act (CESA)	SC	Listed as Candidate for Endangered Species 6/27/17
California Department of Fish and Wildlife	SSC	Species of Special Concern
Bureau of Land Management	None
USDA Forest Service	S	Sensitive
IUCN	NT	Near Threatened

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