Northern leopard frog (Rana pipiens)

Largish brown and tan frog with dark brown spots crouched in the grass
This is the only Washington frog with distinct roundish dark spots in 2 to 3 irregular rows between light-colored ridges along the back and sides.
Category: Amphibians
Ecosystems: Shrubsteppe Riparian areas
State status: Endangered
Vulnerability to climate change (More details)

Moderate-
High

If you see this species, please share your observation using the WDFW wildlife reporting form. Providing detailed information such as a photo and exact coordinates will improve the confidence and value of this observation to WDFW species conservation and management.

Only one native population remains in Washington. Efforts are underway to recover this species in central Grant County. WDFW is partnering with Washington State University, U.S. Fish and Wildlife Service, Oregon Zoo, and Northwest Trek to better understand population status and trends, to improve habitat conditions, and to reintroduce a northern leopard frog population to the Columbia National Wildlife Refuge. 

Northern leopard frogs in Washington have unique genetics traits. Genetic testing on northern leopard frogs found in the Spokane area indicated they are not native to Washington, but likely captive frogs released illegally. These frogs may carry disease and alter the unique genetics of the native northern leopard frogs.  

Description and Range

Physical description

The northern leopard frog is a medium to large (3 to 4 inches snout to vent length) aquatic frog with a slender body, thin waist, long legs, and smooth skin. The dorsal (topside) color is brown or green. The northern leopard frog is the only Washington frog with distinct round or oval dark spots arranged in two to three irregular rows between conspicuous light-colored dorsolateral folds (ridges along back and sides). The presence of these folds separates native Washington True Frogs (Rana species) from other Washington anurans. The northern leopard frog’s spots typically have a light border. Spotting also occurs on the limbs. The dorsolateral folds extent to the groin. The belly is cream or white with no dark markings

Larvae

The tadpole (aquatic larval stage) has an oval body with dorsal eyes, a vent on the right side, a spiracle on the left side and a dorsal fin that originates on the body near the dorsal tail-body junction. The tip of the tail is pointed. The tail fin is translucent with or without fine dark markings. At hatching, tadpoles are uniformly dark. As they increase in size, they develop silver or gold pigmentation over the body and concentrated on the belly. The intestines are clearly visible through the abdominal muscles.

Underwater close up of a northern leopard frog tadpole
Northern leopard frog tadpole found in Grant County. W.P. Leonard, Copyright

Tadpoles of the American bullfrog and Columbia spotted frog are similar and occupy the same range. American bullfrog tadpoles (less than 0.5 inches snout to vent length) have distinct black spots over the dorsal surface of the body. Other references should be consulted to accurately separate leopard frog and Columbia spotted frog tadpoles, but in general, leopard frog tadpoles (greater than 0.5 inches snout-vent length) differ in lacking dark mottling on the tail fin and having abdominal muscles that are nearly transparent.

Eggs

The egg mass is 2.5 to 4 inches in width and attached to vegetation in shallow water. Smaller clusters of 20 to 40 eggs may be present near the main cluster. The ova are less than 0.9 inches in diameter. The gelatinous covering around the eggs is thin resulting in eggs that are packed closely together within the mass.

The Columbia spotted frog is the only amphibian within the Washington range of the leopard frog that also has grapefruit-sized globular egg masses. Leopard frogs do not have multi-clustered egg masses placed together in one pile, but rather they attach single egg masses to vegetation in water over 6 inches deep. Spotted frogs have a thicker jelly coat around the eggs and therefore the eggs do not appear tightly packed within the mass (except when the egg mass is first laid).

For more details about the northern leopard frog, see the Washington Herp Atlas

Ecology and life history

Northern leopard frogs are semi-aquatic, requiring both aquatic and terrestrial habitats. Breeding occurs in shallow, still water sites. Typically these areas are exposed to sunlight and have thin but sturdy vegetation stems for egg attachment. In central Washington, breeding takes place in April. Males vocalize with a low snore followed by low grunts to attract females to breeding locations.

A grapefruit-sized egg mass is deposited just below the water surface and attached to vegetation. Eggs may hatch within a few days or weeks depending on water temperature. Tadpoles forage mainly on algae and detritus, and complete metamorphosis in 60 to 90 days. Newly metamorphosed frogs emerge from ponds starting in mid-July.

During the active season, leopard frogs eat a variety of insects and small frogs. They forage on pond edges, damp meadows, marshes, fields, irrigation ditches, and scrublands. 

They typically overwinter under water, and require deep, well-oxygenated water that does not freeze solid to the sediments.

Northern leopard frogs may be preyed on by many species throughout their life history, but the most common are likely mustelids, bullfrogs, and fish. 

Geographic range

The northern leopard frog has experienced range-wide declines throughout the western states and Canada. Historical occurrences are from the Columbia Plateau, Okanogan and Canadian Rocky Mountain Ecoregions: northern leopard frogs were found throughout eastern Washington, and 17 occupied sites were recognized throughout the Columbia, Crab Creek, Pend Oreille, Snake, Spokane, and Walla Walla river drainages. The last known population of northern leopard frogs in Washington is located in the Columbia Basin Wildlife Area.

This map from the Washington Herp Atlas illustrates the known distribution of northern leopard frog in Washington as of 2016. If you see this species in areas that are not indicated on the map, please share your observation using the WDFW wildlife reporting form.

Northern leopard frog state map:Okanogan,Pend Oreille,Spokane,Grant,Klicikitat,Benton,Walla Walla,Whitman,Asotin counties
Washington Herp Atlas (2017)

For a map of range-wide distribution and conservation status of this species, check out NatureServe Explorer.  

Climate vulnerability

Sensitivity to climate change

Moderate-
High

Limited information was available regarding the sensitivity of Washington’s northern leopard frogs to climate change. They may experience some sensitivity to potential increases in temperature, that could lead to earlier timing of mating and breeding. Their sensitivity would be increased by potential climate-induced changes in their pond habitat. Adults need deep water, seasonal ponds, and wetlands for breeding habitat. Potential warmer, drier conditions could lead to declines in available breeding habitat. After breeding, northern leopard frog  will often forage away from the water’s edge in damp-soil marsh edges and meadows. This habitat  is likely the most vulnerable to climate change because predictions are for more extreme summer drying. This might result in northern leopard frogs having to utilize aquatic habitat more frequently during this season. It is unclear how severe a stressor this change might be. One concern is that it might increase northern leopard frog exposure to bullfrog and fish predation particularly if the leopard frogs are forced to use reservoir habitat because other aquatic water bodies and edges have dried. Drier conditions could even lead to localized population extinctions if breeding ponds become too shallow or disappear completely.

Confidence: Moderate

Exposure to climate change

Moderate-
High

  • Increased temperatures
  • Changes in precipitation
  • Altered hydrology
  • Reduction in non-breeding active season habitat in summer
     
Confidence: Moderate

Regulations

Licenses and permits

Be advised that collection of this species is only permitted under a WDFW Scientific Collection Permit for research and educational activities.

Rules and seasons

Due to the significant reduction in range and abundance of leopard frogs in Washington, and the continued threats to the remaining occupied sites, leopard frog were classified as an endangered species in Washington in 1999. The law protects endangered species and prohibits them from being hunted, taken maliciously, harassed, or possessed. This is for all life stages including adults, juveniles, tadpoles, and eggs. Keeping this species as a pet in Washington is also prohibited because species native to the state cannot be kept in captivity. The only exceptions are for zoos, educational centers, rehabilitation facilities, and research facilities that receive permits from WDFW.

Conservation

This species is identified as a Species of Greatest Conservation Need (SGCN) under the State Wildlife Action Plan (SWAP). SGCN-classified species include both those with and without legal protection status under the Federal or State Endangered Species programs, as well as game species with low populations. The WDFW SWAP is part of a nationwide effort by all 50 states and five U.S. territories to develop conservation action plans for fish, wildlife and their natural habitats—identifying opportunities for species' recovery before they are imperiled and more limited.
This species is identified as a Priority Species under WDFW's Priority Habitat and Species Program. Priority species require protective measures for their survival due to their population status, sensitivity to habitat alteration, and/or recreational, commercial, or tribal importance. The PHS program is the agency's main means of sharing fish and wildlife information with local governments, landowners, and others who use it to protect priority habitats for land use planning.

Conservation Threats and Actions Needed

  • Invasive and other problematic species
    • Threat: Non-native aquatic species including American bullfrogs, mosquito fish and other non-native predatory game fish. Bullfrogs are predatory for all life stages of northern leopard frogs.; mosquito fish prey on amphibian egg masses and tadpoles. Non-native predatory game fish, such as bass, prey on the frogs and tadpoles.
    • Action Needed: 1. Remove mosquito fish from ponds previously occupied by northern leopard frogs. 2. Prevent introduction of non-native fish to ponds occupied by northern leopard frogs. 3. Manage habitat to favor this frog but not favor bullfrogs and fish (example, create seasonal ponds). 4. Create and maintain barriers such as dikes that prevent non-native fish from entering ponds occupied by this species.
    • Threat: Unknown impacts to population from disease.
    • Action Needed: Additional disease monitoring is necessary to determine the extent of the disease threat in the Northern Leopard Frog Management Area on the Columbia Basin Wildlife Area.
    • Threat: Wetland succession and tall emergent vegetation encroachment (example, reed canary grass, phragmites, and non-native cattails) reduces suitability of habitat.
    • Action Needed: Set back succession, reduce tall emergent vegetation and encourage short emergent cover through chemicals and mechanical treatments.
  • Fish and wildlife habitat loss and degradation
    • Threat: Loss of suitable habitat due to water management in the Potholes Reservoir (drawdowns, backups).
    • Action Needed: Create and restore breeding habitat (seasonal ponds).
  • Agriculture and aquaculture side effects
    • Threat: The Odessa Supplemental Feed Route will influence water levels in Potholes Reservoir and may impact the amount of suitable habitat in the Northern Leopard Frog Management Area on the Columbia Basin Wildlife Area.
    • Action Needed: 1. Maintain suitable habitat to allow for dispersal and movement. 2. Monitor population. 3. Pursue opportunities to establish new populations. 4. Use adaptive management to deal with the high level of uncertainty regarding potential habitat changes.

See the Climate vulnerability section for information about the threats posed by climate change to the northern leopard frog.

Living with wildlife

Learn about living with frogs. Understanding wildlife is key to reducing human/wildlife conflicts. The Washington Department of Fish and Wildlife offers a wide range of information designed to minimize conflicts between humans and wildlife, as well as attracting beneficial wildlife and helping residents better understand the animals in their backyards.

Resources

References

Alberta Northern Leopard Frog Recovery Team. 2005. Alberta Northern Leopard Frog Recovery Plan, 2005-2010. Alberta Sustainable Resource Development, Fish and Wildlife Division, Alberta Species at Risk Recovery Plan no. 7. Edmonton, AB. 26pp.

Germaine, S., and D. Hays. 2007. Distribution and post-breeding environmental relationships of northern leopard frogs (Rana pipiens) in Grant County, Washington. Final Report. Washington Department of Fish and Wildlife, Wildlife Program, Olympia.

Hallock, L. A. and K. R. McAllister. 2005. Northern Leopard Frog. Washington Herp Atlas. 2009. A cooperative effort of Washington Natural Heritage Program, Washington Department of Fish and Wildlife, U.S.D.I. Bureau of Land Management, and U.S. Forest Service. Map products updated March 2017. Provisional PDF version of the website (2005-2019) created July 2019. 250 pp. 

WDFW publications 

PHS Program

Status reports

WDFW educational resources

Other resources