Northern red-legged frog

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The northern red-legged frog (Rana aurora) is a true frog found along the Pacific coast in North America. It has smooth skin that can be greenish to reddish-brown, bright red hind legs, dark spots on its back, and a dark mask on its face. Its body is slim with a long waist, and its eyes are golden-brown.

Range and habitat
This frog lives from northern California up through western Oregon and Washington to southwestern British Columbia and Vancouver Island. It also occurs in the southern Cascade Range and is introduced in Alaska. It uses both upland land and aquatic habitats, especially ponds, streams, and marshes with lots of vegetation and sunny shorelines. It needs places to hide from predators.

Appearance and relatives
The northern red-legged frog is part of the true frog family, Ranidae. It is one of two red-legged frogs, the other being the California red-legged frog. They were once thought to be the same species, but DNA and anatomy show they are separate. Unlike the California red-legged frog, the northern red-legged frog does not have vocal sacs.

Size and behavior
Adults are larger in females, up to about 10.7 cm, while males are usually up to about 8.1 cm. Males arrive at breeding sites earlier and may defend territory. They jump well and spend part of the year on land and part in the water.

Diet
Adults eat insects, worms, small snails, and crustaceans, and they may also eat small fish or other small animals. Tadpoles eat algae.

Breeding
Northern red-legged frogs typically breed from January to March. Males call underwater at the breeding ponds, and females lay eggs in shallow water among submerged vegetation. A single egg mass can contain hundreds to thousands of eggs. Eggs are 2–3 mm wide and hatch after about 3–5 weeks. Tadpoles are herbivorous and grow into juvenile frogs after several weeks to months, then move to terrestrial habitats.

Conservation
The IUCN lists the species as Least Concern, but its numbers are falling in some areas. Road traffic during their seasonal migrations to breeding ponds is a major threat, especially in urban areas. In Oregon, this frog is a conservation concern. To help, volunteers in Portland run programs to move frogs safely across roads, and projects like wildlife undercrossings on highways aim to reduce road deaths.

Summary
The northern red-legged frog is a distinct, cliff-dwelling-looking frog of the Pacific Northwest, recognizable by its red legs, smooth skin, and dark facial mask. It lives in wet, vegetated habitats and breeds in winter to early spring, facing threats mainly from road roads and urban development. Conservation efforts in some areas are helping reduce these dangers.