Description: Rana aurora reaches from 2 to 5.25 inches in length. It is reddish brown to gray and contains many poorly defined dark specks and blotches, which are absent on the back and top of its head. A light stripe on its jaw borders its dark mask. Folds are present on its back and sides, and the underside is yellow with red on the lower abdomen and hind legs. Its toes are not fully webbed. Females grow larger than males. Males, however, have enlarged forearms and swollen thumbs. Rana aurora aurora has very smooth and thin skin and an unspotted dorsal surface.

Habitat: he still waters of ponds, marshes or stream pools are essential for northern red-legged frog breeding habitat; moreover, this species of frog is considered unusually highly oriented to its aquatic habitat, with a clear preference for thickly vegetated shoreline. R. aurora requires cover, since it is subject to predation by various fishes, snakes, birds, mammals, and even certain other amphibians. When this frog senses danger, it will quickly plunge to depths of one meter or more to seek safety in the benthic zone of a pond.

Range: The northern red-legged frog is found in the Pacific Northwest, in western Oregon, western Washington and southwestern British Columbia, including Vancouver Island. In California, its range includes every coastal county from southern Mendocino County northward. While it occurs primarily in the Northern California coastal mountain ranges, it is not found above an elevation of 3900 feet. It also occurs somewhat less commonly in the southern Cascade Range.

Found in these States: AK | CA | OR | WA

Diet: Mature R. aurora specimens prey upon terrestrial insects, but will also take small snails and crustaceans; also, they will consume worms, tadpoles, small fish. and even small frogs of other species. The tadpoles are herbivorous.

Reproduction: Males and females begin to move to the breeding sites as early as October, and sometimes as late as January, depending on latitude, cumulative rainfall for the season, and average temperature. Typically, stable minimum temperatures of 42 to 44 ℉ are required to induce breeding. Observations of adult migration are best made on moonlit nights with light rains. The male is thought to defend his territory, once he is in the breeding pond area, using nocturnal displays. In fact, most activity is at night, especially enhanced by periods of light rain. The actual courtship behaviors commence in January in the California part of the range, and as late as March in northerly regions. In any case, the breeding season terminates in July at the latest, and earlier in the drier locales.

Each female produces 200 to 1100 eggs per season, and attaches the egg cluster to submerged vegetation or rotting logs, characteristically seven to 0.5 inches below the pond surface. Egg clusters are typically about 0.3 inches in diameter, and may disperse into an irregular form underwater. Eggs hatch in 39 to 45 days, and tadpoles require about 80 days to attain metamorphosis.

Oviposition generally takes place in densely vegetated, shallow portions of wetlands with little current, and in unusual cases, egg masses have been observed in water up to 16.4 inches in depth. Breeding sites can be either permanent or temporary, with inundation usually necessary into June for successful metamorphosis. The June date is based on Oregon conditions; in Northern California, metamorphosis occurs in late May or early June. Breeding is initiated when water temperatures exceed about 42 ℉ (usually in January), but can be as late as March in the extreme northern part of the range.

Status: Large range in western North America; substantial declines in some areas; still widespread, common, and apparently secure in many areas; warrants rangewide monitoring.

Subspecies: None

Taxonomy: