California Reptiles & Amphibians

Rana sierrae - Sierra Nevada Yellow-legged Frog

Formerly Rana muscosa - Mountain Yellow-legged Frog


Click on a picture for a larger view





Historical Range in California: Red


Listen to this frog:


A short example


More sounds of
Rana sierrae


More pictures and information:


Page 2 - Breeding, Eggs, Tadpoles



Adult, Alpine County
Adult, Alpine County
Adult, Alpine County
Adult, Alpine County
Adult, Alpine County
Adult, Alpine County
Adult, Alpine County
Juvenile, Alpine County
Adult male, Alpine County
Calling adult male, Alpine County
Adult male, Alpine County
Underside of adult showing yellow legs, Alpine County
Adult, Alpine County
Underside, Inyo County © Todd Battey
Juvenile, Alpine County
Adult, 11,100 ft., Mono County
© Chris Lima
Congregation of adult frogs, Fresno County. These frogs were discovered on the south-facing slope of a barely ice-free alpine lake (11,000 ft.). They are covered with pollen, wind-blown from lower altitudes, which coated the area.
© Ceal Klingler
Amplexing adults, Alpine County
Eggs
Mature Tadpole

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


Habitat
Habitat, Alpine County
Habitat, 8,800 ft., Alpine County
Habitat, 8,800 ft., Alpine County
Habitat, Mono County
   
Habitat, Fresno County
© Vance Vreedenburg

Habitat, Inyo County © Todd Battey
   
Short Videos
These are four videos of three different male frogs calling during an early summer afternoon in Alpine County. Running water, birds, insects, and an occasional Pacific Treefrog are heard in the background.
 
Several pairs of male and female frogs in amplexus are seen in this video with attempts by other males to steal the females. They are successfully fought off by the amplexing males, usually by a strong kick, but sometimes a long wrestling match ensues. Several groups of male frogs are seen during the breeding season chasing and amplexing each other. You can hear release calls in the first few scenes. This behavior continued for hours, so it did not appear that they were mistaking each other for females they could breed with, but that it was some kind of territorial behavior between males. Or they could have been practicing their pouncing skills for when they encountered females in the future. (This is a long video which might take some time to download.) Two males are seen during the breeding season chasing and amplexing each other until one leaves and the other begins calling.  
Description
Size
Adults are moderate in size, 1.5 - 3.5 in. long from snout to vent (4.0 - 8.9 cm).
Appearance
Variable in color - olive, yellowish or brown above, with varying amounts of black or brown markings. Pale orange to yellow below and underneath the hind legs. Indistinct dorsolateral folds. No dark face mask. Smells like garlic when handled. Differs from Rana muscosa by having relatively shorter legs and a significantly different mating call.
Voice  (Listen)
The call is a short and rasping call often accellerated and rising at the end, sometimes preceeded by calls that don't rise at the end. Calls primarily underwater during the day, but may also call at night. This frog has no vocal sacs.
Behavior
A mountain frog of high elevations. Chiefly diurnal. Usually found close to water. Rarely occurs where predatory fishes have been introduced. Probably spends the winter at the bottom of frozen lakes. Emerges shortly after snow melts. In years of heavy snow, may only be active for about 3 months. Rarely occurs where predatory fishes have been introduced.
Diet
Eats a variety of terrestrial and aquatic invertebrates and tadpoles. May also consume dead frogs and its own eggs. Frogs tend to sit and wait until they see prey come within range, then they strike, or creep up a little then strike, using their large sticky tongue to catch the prey and bring it into the mouth.
Reproduction and Young
Reproduction is aquatic. Fertilization is external. Mating and egg-laying occurs in water shortly after the snows have melted and adults have emerged from hibernation, which can be any time from May - August. Adults tend to live around the breeding pond, so most do not need to travel to the breeding site.

A cluster of 100 - 350 eggs (average 233) is laid in shallow water and is left unattached in still waters, but may be attached to vegetation in flowing water. Egg-laying sites must be connected to permanent lakes or ponds that do not freeze to the bottom in winter, because the tadpoles overwinter, possibly taking as many as 3 or 4 summers before they transform.
Range
Historically, Rana sierrae ranged "...from the Diamond Mountains north-east of the Sierra Nevada in Plumas County, California, south through the Sierra Nevada to the type locality, the southern-most locality (Inyo County). In the extreme north-west region of the Sierra Nevada, several populations occur just north of the Feather River, and to the east, there was a population on Mt Rose, north-east of Lake Tahoe in Washoe County, Nevada, but it is now extinct. West of the Sierra Nevada crest, the southern part of the R. sierrae range is bordered by ridges that divide the Middle  and South Fork of the Kings River, ranging from Mather Pass to the Monarch Divide. East of the Sierra Nevada crest, R. sierrae occurs in the Glass Mountains just south of Mono Lake (Mono County) and along the east slope of the Sierra Nevada south to the type locality at Matlock Lake (Inyo County)." (Vredenburg, et al, 2007.)
Habitat
Inhabits lakes, ponds, meadow streams, isolated pools, and sunny riverbanks in the Sierra Nevada Mountains. Waters that do not freeze to the bottom are required. Open stream and lake edges with a gentle slope up to a depth of 5-8 cm. seem to be preferred.
From 984 ft. - over 12,000 ft. elevation (370 - 3,660 m.)
Taxonomic Notes
According to a February, 2008 petition by the Center for Biological Diversity and Pacific Rivers Council to list the Sierra Nevada Mountain Yellow-legged Frog as an Endangered Species, "The mountain yellow-legged frog in the Sierra Nevada is geographically, morphologically and genetically distinct from mountain yellow legged frogs in southern California. It is undisputedly a 'species' under the ESAOs listing criteria and warrants recognition as such."

Vredenburg, V. T., R. Bingham, R. Knapp, J. A. T. Morgan, C. Moritz & D. Wake (2007. Journal of Zoology 271: 361–374) have determined that this taxon consists of two species, which they name Rana muscosa - Sierra Madre Yellow-legged Frog, and Rana sierrae - Sierra Nevada Yellow-legged Frog. More from the CNAH.

In 2008, the Society for the Study of Amphibians and Reptiles recognized two species, Rana muscosa - Southern Mountain Yellow-legged Frog , and Rana sierrae - Sierra Nevada Yellow-legged Frog.
Conservation Issues  (Conservation Status)
Endangered and absent from a significant part of its historic range. The decline has been attributed to many factors, including introduced non-native trout, airborne pollution, cattle grazing, ozone depletion, mining pollution, public dumping, and chytrid fungus. Fish introductions have stopped in some areas, such as National Parkland, they continue in others. But while it has been documented that introduced trout are substantially reducing the numbers of the frogs, frogs have also disappeared in one watershed where no trout have been introduced, which suggests multiple causes for their decline.
Taxonomy
Family Ranidae True Frogs
Genus Rana True Frogs
Species sierrae Sierra Nevada Yellow-legged Frog

Original Description
Rana muscosa: Camp, 1917 - Univ. California Publ. Zool., Vol. 17, No. 9, p. 118

from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz

Rana sierrae:

Vredenburg, V. T., R. Bingham, R. Knapp, J. A. T. Morgan, C. Moritz & D. Wake (2007. Journal of Zoology 271: 361–374)

Meaning of the Scientific Name

Rana - Frog - "Rana" probably mimics how the Romans heard their call.
sierrae -
refers to the Sierra Nevada Mountains

Taken in part from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz

Alternate Names
Rana muscosa - Mountain Yellow-legged Frog

Related or Similar California Frogs
Rana aurora
Rana boylii
Rana cascadae
Rana catesbeiana
Rana draytonii
Rana muscosa
Rana pipiens
Rana pretiosa
Rana yavapaiensis

More Information and References
Natureserve Explorer

California Dept. of Fish and Game

AmphibiaWeb

Center for Biological Diversity

Dr. Roland Knapp's site

Rescuing a Dying Breed - Saving the Southern California Mountain Yellow-legged Frog

The Mountain Yellow-legged Frog - Can They Be Saved?

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.

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.


Basey, Harold E. Discovering Sierra Reptiles and Amphibians. Yosemite Association and Sequoia Natural History Association, 1976, 1991.

Davidson, Carlos. Booklet to the CD Frog and Toad Calls of the Pacific Coast - Vanishing Voices. Cornell Laboratory of Ornithology, 1995.

Vredenburg, V. T., R. Bingham, R. Knapp, J. A. T. Morgan, C. Moritz & D. Wake (2007. Journal of Zoology 271: 361–374)

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) 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 G1 S1 Critically Imperiled
World Conservation Union - IUCN Red List




IUCN:EN Endangered
 


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