This species is the largest native frog in the western United States, ranging from 1.5 to 5.1 inches in length.
The diet of California red-legged frogs is highly variable. Invertebrates are the most common food items, although vertebrates such as Pacific tree frogs and California mice can constitute over half of the prey mass eaten by larger frogs. Larvae likely eat algae.
California red-legged frogs breed from November through March with earlier breeding records occurring in southern localities. California red-legged frogs are often prolific breeders, typically laying their eggs during or shortly after large rainfall events in late winter and early spring. Embryos hatch 6 to 14 days after fertilization, and larvae require 3.5 to 7 months to attain metamorphosis.The California red-legged frog has been extirpated or nearly extirpated from 70 percent of its former range."
From: Helping Our Peninsula's Environment
Picture of California Red-legged Frog from: sfbaywildlife