California Red-legged Frog
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| Rana draytonii |
The California Red-legged frog (Rana draytonii) is a species of frog within the family Ranidae also known as the "true frogs". It was earlier classified as a subspecies, Rana aurora draytonii, of the Red-legged Frog, but in current times is considered a recognized species in and of itself. The range of this frog is the coastal mountains of California from Baja California to Marin County. Above Marin County a closely related species, Northern Red-legged Frog is found.
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[edit] Physical description
The California Red-legged Frog is a moderate to large (4.4-14 cm) species of frog. The dorsum is brown, grey, olive or reddish color with black flecks and dark, irregular, light-centered blotches and is coursly granular. There is a dark mask with a whitish border above the upper jaw, and black and red or yellow mottling in the groin. The lower abdomen and the underside of its hindlegs are red. Males can be recognized by their enlarged forelimbs, thumbs, and webbing. Juveniles have more pronounced dorsal spotting, and may have yellow, instead of red markings on the underside of the hindlegs. A characteristic feature of the red-legged frog is its dorsolateral fold, which is visible on both sides of the frog extending roughly from the eye to the "hip." The California red-legged frog was listed as a threatened species by the United States Fish and Wildlife Service in 1996.
[edit] Ecology and behavior
It is estimated that this species has disappeared from 70% of its range and is now only found in about 238 streams or drainages in 23 counties of California. Breeding occurs from November to March, however breeding has been recorded earlier in the southern limits of its range. This species inhabits dense, shrubby or emergent riparian vegetation associated with deep still or slow moving water. This frog estivates in small mammal burrows or under damp leaf litter. The California Red-legged Frog is an important food source for the endangered San Francisco Garter Snake.
[edit] Human relations
After years of litigation initiated by land developers organizations, specifically the Home Builders Association of Northern California, and scientific back-and-forth. The U.S. Fish and Wildlife Service announced in April 2006 the designation of about 450,000 acres (1800 km²) of critical California habitat for the threatened frog. This protected habitat did not include any land in Calaveras County, the setting of Mark Twain's short story, "The Celebrated Jumping Frog of Calaveras County", which features this species.
[edit] References
- Santos-Barrera et al (2004). Rana aurora. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 05 May 2006. Database entry includes a range map and justification for why this species is near threatened
- This article is based on a description from "A Field Guide to the Reptiles and Amphibians of Coastal Southern California", Robert N. Fisher and Ted J. Case, USGS, http://www.werc.usgs.gov/fieldguide/index.htm.
- U.S. Fish and Wildlife Service, http://www.fws.gov/endangered/features/rl_frog/rlfrog.html
- "Calif. Frog at Center of Protection Debate" Washington Post
