California Red-legged Frog (Rana draytonii)

Rana draytonii ranges from 1.5 to 5 inches in length, making it the largest native frog in the Western United States (Wright and Wright 1949). Adult females are significantly longer than males, with an average snout- urostyle length of 138 mm versus 116 mm for adult males (Hayes and Miyamoto 1984). The hind legs and lower abdomen of adult frogs are often characterized by a reddish or salmon pink color, and the back is brown, gray, olive, or reddish brown, marked with small black flecks and larger irregular dark blotches ( Recovery Plan for the California Red-legged Frog 2002; Stebbins 1985). Dorsal spots often have light centers, and in some individuals form a network of black lines (Stebbins 1985). Dorsolateral folds are prominent. Tadpoles range in length from 14 to 80 mm, and are a dark brown or olive, marked with darker spots (Storer 1925).

Rana draytonii is widely believed to have inspired Mark Twain's fabled story, "The Celebrated Jumping Frog of Calaveras County." The California red-legged frog was Federally listed on June 24, 1996. R. draytonii differs from its close relative R. aurora , the Northern red legged frog, in several ways. Adult R. draytonii are 35 to 40 millimeters longer than adult R. aurora (Hayes and Miyamoto 1984). The dorsal spots of R. draytonii are more numerous, and usually have light centers (Stebbins 1985). R. draytonii also has rougher skin, shorter limbs and smaller eyes than R. aurora (Stebbins 1985). R. draytonii has paired vocal sacs and typically calls from the air , while R. aurora lacks vocal sacs ( Hayes and Krempels 1986; Licht 1969). Egg masses in R. draytonii are deposited such that the mass floats at the surface (Hayes and Miyamoto 1984), whereas R. aurora submerge the mass in deeper water (Licht 1969; Storm 1960). R. draytonii breed from November to April (Storer 1925), while R. aurora breeds from January to March (Nussbaum et al 1983).