California Red-legged Frog
A California red-legged frog (Rana draytonii) sitting in the grass next to a pond in San Mateo County, CA. This species can be distinguished from other native frogs due to its large size (the largest native frog west of the Rockies), the fold of skin that extends from the eye to the hind legs (see note), and the tinge of red on the underside of the hind legs..
The range of this species has declined dramatically since the 1800s due in large part to a combination of excessive harvest for human consumption (mostly in the 1800s) as well as habitat loss associated with agricultural, industrial and residential development. The species has also suffered as a result of the introduction of the bullfrog (Rana catesbeiana; native only east of the Rockies), which is larger than and preys on red-legged frogs and in many cases is a stronger competitor.
The California red-legged frog is classified as 'Threatened' by both State and Federal authorities, but in the area where this pictures was taken it is relatively common.