The California red-legged frog is a species of frog found in California (USA) and northern Baja California (Mexico). It was formerly considered a subspecies of the northern red-legged frog (Rana aurora).
This species has disappeared from an estimated 70% of its range, and is now only found in about 256 streams or drainages in 28 counties of California. However, the species is still common along the coast, and most of their population declines are in the Sierra Nevada and Southern California. The California red-legged frog is an important food source for the endangered San Francisco garter snake in San Mateo County.
Breeding occurs from November to March, or sometimes earlier toward the southern limits of its range. The male frog's advertisement call is a series of a few small grunts, usually given while swimming around under water. Choruses are weak and easily missed. This species is usually active in daylight and inhabits dense, shrubby, or emergent riparian vegetation and still or slow-moving perennial and ephemeral water bodies that also serve as breeding sites.
This frog is listed as threatened and is protected by federal and California law. The main cause of the population decline is habitat loss and destruction, but introduced predatory species, such as American bullfrogs, might also be a factor.