Alaska Herpetological Society
Red-legged Frog (Rana aurora)
Adults: Stout, medium to large frog measuring up to 13.6cm (5.4in). The head is broader than long and the snout rounded. The light jaw stripe usually ends at the shoulder and the eyes look to the side. Hind legs are long, belly is reddish-brown to grey and the dorsal folds are distinct. Bold cream to yellow and black (or red) mottling in the groin, underside of the hind legs and lower abdomen are translucent red (yellowish in young animals.
Eggs: Large-sized eggs, averaging about 3mm in diameter are laid in soft, grapefruit to cantaloupe sized mass, usually attached to submerged sticks and vegetation in the deepest water available.
Tadpoles: Stubby with a high dorsal fin. The mouth has three tooth rows on top and four on the bottom (need microscope). The larger tadpoles are dark brown with black splashed on the tail.
FACTS
1. This frog occurs in meadows, woodlands, and forests but is usually found in or near ponds, marshes and streams. It prefers ground cover and aquatic or overhanging vegetation.
2. The species was introduced by a schoolteacher at Freshwater Bay on Chichagof Island near Hoonah in 1982 / 1983. No records elsewhere, YET!
3. Male mating call is a weak stuttering “uduh-uh-uh-rowr” lasting 1-3 seconds with the throat enlarging at the sides. Usually call at night while submerged.
4. Noting the underside of rear legs is the a good way to distinguish from a young Bull Frog. Rear legs longer than Columbia Spotted Frog.
Red-legged Frog Video
(NOTE: While Red-legged Frogs are threatened throughout much of their native range, they are considered exotic invasives in Alaska!)