Saving the northern leopard frog
Once found throughout North America, northern leopard frogs are rapidly disappearing from their native habitats in Washington, Oregon and western Canada. In Washington, they have been listed as endangered since 1999. Only one known population remains there, and the Oregon Zoo is at the forefront of restoring this population.
Northern leopard frog populations in the Pacific Northwest remained healthy until the introduction of the American bullfrog. Native to the eastern United States but considered invasive here, American bullfrogs are the largest frog species on the continent. They have been driving northern leopard frogs to the brink of extinction through predation, competition, and the spread of disease.
In response, the zoo participates in the northern leopard frog recovery effort in partnership with the Washington Department of Fish and Wildlife, U.S. Fish and Wildlife Service, Washington State University and Northwest Trek Wildlife Park.
To give the frogs a head start and improve their chances of surviving predators, WDFW biologists collect some egg masses in winter and bring them to the zoo. The frogs hatch and grow in a protected setting through spring and summer before being released back into the Columbia National Wildlife Refuge. This head-starting effort helps the zoo and its conservation partners rebuild the northern leopard frog population in the region.
As of 2025, 1,045 Oregon Zoo-reared northern leopard frogs have been released to the wild.
In 2025, for the first time, biologists documented zoo-reared northern leopard frogs surviving in the wild at the Columbia National Wildlife Refuge in eastern Washington, even as the American bullfrog remains in the area.
The life of a northern leopard frog
Northern leopard frogs grow two to 4.5 inches long, weigh between a half ounce to three ounces and live four to five years in the wild, and as long nine years in human care. They are active in both daytime and nighttime.
Northern leopard frogs breed and develop in water. They begin spending time on land as they grow. During summer, northern leopard frogs live in grasslands, wetlands, rivers and streams. During winter, they hibernate in bodies of water that do not freeze completely. As coldblooded amphibians they can’t survive freezing conditions.
Northern leopard frogs hunt for food in moist grassland areas. They primarily eat insects, as well as spiders and leeches. Predators include turtles, snakes, fish, birds, raccoons and other frogs. They are most threatened by invasive American bullfrogs.
Northern leopard frogs at the zoo
The northern leopard frog head-starting program is located behind the scenes in the Great Northwest area.
