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Oregon Spotted Frog (Rana pretiosa)

photo by William Flaxington

Common Name: Oregon Spotted Frog
Scientific Name: Rana pretiosa
Family: Ranidae – True Frog family
Locations: United States and Canada
US Locations: California, Oregon, and Washington
Size: 1.75 – 4 inchesĀ (4.4 – 10.1 cm)

The Oregon Spotted Frog is listed as Vulnerable by the International Union for the Conservation of Nature (IUCN) Red List and as threatened by the United States federal government. The frogs are most likely are gone from California. The two primary threats are introduced species and habitat destruction / alteration. Much of the wetlands that they call home have damaged due to construction of dams and water removal for farms and cities. Some of the remaining habitat has been invaded by the American Bullfrog (Rana catesbeiana) or introduced game fishes. These introduced predators feast on the Oregon Spotted Frog and their tadpoles. Removing these predators would help the frog’s numbers bounce back.

photo by USFWS

Breeding takes place after the snow melts, generally in February and March at low elevations and May and June at higher elevations. Breeding only lasts 2 to 4 weeks long. Males will gather in the shallows of marshes and lakes at call for the females. Females will select a male to mate. They will then enter the amplexus position and the females will lay their eggs and the male will fertilize. Females lay around 650 eggs. The eggs hatch into tadpoles between 18 and 30 days. The tadpoles then take 110 to 130 days to complete their metamorphosis.

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