Amphibians
Northern Red-Legged Frog
Rana aurora · also called red-legged frog
Beside a shaded forest pond in the Pacific Northwest, a northern red-legged frog launches into a powerful leap the instant a shadow crosses overhead, a reddish flash on its legs briefly visible before it vanishes beneath the water’s surface.
Overview
The northern red-legged frog, Rana aurora, is a forest-dwelling frog native to cool, shaded wetland and stream habitat across the Pacific Northwest. Its relatively recent split from the closely related California red-legged frog and its vulnerability to introduced predators such as bullfrogs make it one of the more taxonomically and ecologically notable frogs in the region.
A species defined by a line on a map
For years, this frog’s identity was folded into a single species stretching from the Pacific Northwest down into California, until closer study drew a genuine line between two populations that had quietly been evolving their own separate paths all along.
Status
Least Concern, though decreasing in parts of its range — present across much of the Pacific Northwest but affected locally by habitat loss and predation from introduced species such as bullfrogs.
Northern Red-Legged Frog: common questions
How is the northern red-legged frog different from the California red-legged frog?
The northern red-legged frog was formerly grouped together with the California red-legged frog as a single species until genetic and physical evidence led researchers to split them apart, and today the two are recognised as distinct species with largely separate ranges, the northern species occupying the Pacific Northwest and the California species found farther south.
Why is it called the red-legged frog?
A northern red-legged frog displays a reddish wash on the underside of its hind legs and lower belly, a distinctive colouration visible mainly when the frog is viewed from below or when its legs are extended, which gave the species its common name.
Why has the northern red-legged frog declined in some areas?
The northern red-legged frog has declined in parts of its range due to predation by introduced species such as bullfrogs and non-native fish, which prey on the frog's eggs, tadpoles, and adults, alongside broader habitat loss affecting the forested wetlands the species depends on.
Where does the northern red-legged frog live?
The northern red-legged frog is native to forested wetland, pond, and stream habitat across the Pacific Northwest, including western Washington, Oregon, and parts of British Columbia, generally favouring cool, shaded water within forest cover.