Mountain Yellow-legged Frog (Rana muscosa) Fact Sheet: Distribution & Habitat

Endemic Range (Hammerson 2008)

• Southern Sierra Nevadas (of California)
• Transverse Ranges (of southern California)
  • San Gabriel Mountains, San Jacinto Mountains, San Bernardino Mountains, Palma Creek, Palomar Mountain

Historic Distribution (Jennings and Hayes 1994)

• About 166 locations in creeks and drainages of mountains of southern California

Current Distribution (additional information in Population & Conservation Status)

• Southern California (USGS 2012 with survey data from 2011, unless otherwise noted)
  • 5 streams in the San Gabriel Mountains
  • 1 stream in the San Bernadino Mountains
  • 3 streams in the San Jacinto Mountains
    •  1 additional stream as an experimental re-establishment area (Indian Creek, Hall Canyon)
      • First release in 2010; adult frogs now found at site (N. Gardner, personal communication 2015)
  • No extant populations found in Palomar Mountain or any other San Diego County locations (Lemm 2006)
• Southern Sierra Nevada
  • Northern border of Rana muscosa range: ridges separating headwaters of South Fork Kings River from Middle Fork Kings River, from Mather Pass to Monarch Divide (Vredenburg et al. 2007)
  • Rana sierrae is found north of this boundary
• All known populations and majority of habitat within areas managed by the U.S. Forest Service (Hammerson 2008)

Conservation Status (additional information in Managed Care and Population & Conservation Status)

• IUCN Status
  • Endangered (2008 assessment) (Hammerson G. 2008)
• CITES Status
  • Not listed (as of May 2019) (UNEP 2019)
• Captive Population
  • San Diego Zoo Wildlife Alliance (N. Calatayud and N. Gardner, personal communications, 2015)
    • First San Bernardino animals brought into managed care in 2003
    • First San Jacinto animals brought into managed care in 2006
      • Multiple reintroductions in San Jacinto range
        • Indian Creek, Hall Canyon releases since 2010
        • • Adult frogs now at site
        • Fuller Mill Creek, May and August 2015 releases
          • May 2015 release of 711 tadpoles; 400 retained for further development and future release
        • • August 2015 release of an additional 200 late-stage tadpoles and 27 juveniles
        • Dark Canyon, 2016
          • 111 young frogs released in May
• Populations in the wild
  • Only 166 were believed to exist in southern California in 2009 (Backlin 2013)

• Elevation
• 1,221-7,557 feet (Lemm 2006)
• Permanent streams, rivers, creeks, pools
• Cold, shaded, rocky watercourses
• Breeding requires constant presence of water (metamorphosis can take up to 2 years, in the wild)     
• Natural flow of water with periodic flooding
• Rocks, logs or gravel piles above water's surface for resting and sunning
• Overhanging banks, crevices, branches, foliage for protection from predators
• Surrounding vegetation
• Alders, willows, sycamores, cottonwoods, conifers, maples

Historic distribution map of Rana muscosa (Zweifel 1955, p. 232).

Current and historic distribution of Rana muscosa in southern California.

Extensive surveys have been performed by USGS at over 200 additional locations in all four mountain ranges within the historical distribution of the species. No other occupied areas have been identified (USGS 1998–2012; USGS GIS data). Image & information credit: USFWS 2012. Some rights reserved. Click here or on map for larger view (page 13).

Image credit: United States Fish and Wildlife Service (USFWS). 2012. Mountain Yellow-Legged Frog (Rana muscosa) Southern California Distinct Population Segment 5-year Review: Summary and Evaluation. Carlsbad Fish and Wildlife Office, Carlsbad, California.:U.S. Fish and Wildlife Service.

Click here for IUCN map of Rana muscosa distribution in California.

Backlin et al. (2004)
Calatayud (2015)
Jennings and Hayes (1994)
Lemm (2006)
Stebbins (1951)
USFWS (2002)
USFWS (2012)
Vredenburg (2007)