There are approximately 70 mammals found in King County -- from tiny shrews to visiting gray whales. Scroll down this page for a list of them grouped by family. The University of Puget Sound's Slater Museum maintains a list of all the mammals found in Washington state.

There are a couple mammals that end up causing concern to King County residents each year: Elk and Beavers. We've devoted an entire website to beavers to present more thorough information about them and beaver-related challenges and solutions. Here are a couple other resources that might be useful:

• WDFW's Elk Fact Sheet, including "Living with Elk"
• WDFW's Beaver page, including "Living with Beavers"

Big predators such as black bears and cougars can also present wildlife-related challenges in an urbanizing environment. Check out our Urbanization and Biodiversity page to learn more about living with these animals.

Marine mammals

Killer whales (Orcas) are the most common whale species seen in King County waters. The Southern Resident killer whales were federally listed as endangered in November 2005 because of population declines. In July 2011, there were 88 whales in this population, and as of June 2019 the population stands at 76. The southern resident population feeds solely on salmon, whose populations have declined from historic levels. Another primary threat to this population is reduced reproductive capacity, meaning they are not having as many babies. A third big threat is declining health as a result of extremely high levels of pollutants in their bodies. There is a lot of information available about the Southern Resident population:

• The Center for Whale Research's Orca Survey 
• The Whale Museum's Issues Affecting the Southern Resident Orcas
• Vessel Regulations in Washington State for Southern Resident Killer Whales
• NOAA's Killer Whale Fact Sheet
• The Orca Network, a non-profit organization dedicated to raising awareness of the whales of the Pacific Northwest
• 13 whales you can see in the Pacific Northwest, and how to identify them, from Oregon Live
• State of Washington's 2017 Periodic Status Review for Blue, Fin, Sei, North Pacific Right, and Sperm Whales

Although this page is about mammals in King County, some sightings in Puget Sound and off the coast of Washington are incredibly interesting. These news articles about different whale species in our region span a decade:

• Puget Sound whale sightings in COVID-19 times, The Islands' Sounder, April 20, 2020
• Gray whales return: Researchers wonder why 'Sounders' seem healthier than others, Kitsap Sun, March 21, 2020
• Orcas sighted in Puget Sound, including rare 'little white whale', KOMO News, October 13, 2019
• Rare Sighting of Blue Whales off the Washington Coast, OPB, August 13, 2019
• Salish Sea's 'humpback comeback' is a good sign, but concerns remain, Crosscut, August 16, 2019
• 2nd confirmed sighting of Fin whale in Puget Sound since 1930, San Juan Islander, July 19, 2016
• Gray whale spotted in backwater of south Puget Sound, KOMO News, June 19, 2013
• Dead [fin] whale draws crowd to Puget Sound beach, Associated Press, April 15, 2013
• Southern Resident Orcas have a new calf, Seattle PI, December 20, 2011
• Long-beaked tropical dolphins spotted in Puget Sound, Seattle Times, June 21, 2011
• Rare Blue Whales return off the Washington Coast, Seattle PI, December 14, 2011

Other related information

• WDFW's page on squirrel species in the State of Washington.
• American Cetacean Society - Puget Sound Chapter.
• Search for listed species in Washington State with WDFW's searchable database.
• Burke Museum provides information about mammals in Washington State.
• Slater Museum of Natural History maintains a mammals web site. The list of mammals below is taken directly from their list: only King County's mammals are included.

Mammals found in Washington state

Order Rodentia: Rodents

Aplodontidae: Mountain Beaver

• Mountain Beaver, Aplodontia rufa. Forests and clearings. 

Sciuridae: Squirrels

• Yellow-pine Chipmunk, Tamias amoenus. Subalpine zone.
• Townsend's Chipmunk, Tamias townsendii. Wet forests.
• Hoary Marmot, Marmota caligata. Subalpine and alpine zones. 
• Cascade Ground Squirrel, Spermophilus saturatus. Meadows and open woodlands. 
• Eastern Gray Squirrel, Sciurus carolinensis. Cities and towns. Introduced from E U.S.
• Eastern Fox Squirrel, Sciurus niger. Cities and towns. Introduced from E North America.
• Douglas' Squirrel, Tamiasciurus douglasii. Conifer forests. 
• Northern Flying Squirrel, Glaucomys sabrinus. Forests. 

Castoridae: Beavers

• North American Beaver, Castor canadensis. Wetlands, streams, lakes, ponds.

Cricetidae: Cricetid Rats

• Deer Mouse, Peromyscus maniculatus. All habitats but much less common in wet forests inhabited by Peromyscus keenii.
• Forest Deer Mouse, Peromyscus keenii. Forests. 
• Bushy-tailed Woodrat, Neotoma cinerea. Talus and rocky areas at all elevations.
• Gapper's Red-backed Vole, Clethrionomys gapperi. Forests. 
• Heather Vole, Phenacomys intermedius. Subalpine forest and meadows.
• Townsend's Vole, Microtus townsendii. Marshes, wet meadows, and riparian woodlands. 
• Long-tailed Vole, Microtus longicaudus. Moist habitats, lowlands and mountains. 
• Creeping Vole, Microtus oregoni. Moist habitats. 
• Water Vole, Microtus richardsoni. Streams and wet meadows. 
• Muskrat, Ondatra zibethicus. Wetlands and other freshwater aquatic habitat.

Muridae: Murid Rats

• Black Rat, Rattus rattus. Most habitats, especially near habitations. Introduced from Europe.
• Norway Rat, Rattus norvegicus. Usually associated with humans. Introduced from Europe.
• House Mouse, Mus musculus. Most habitats, especially near habitations. Introduced from Europe.

Zapodidae: Jumping Mice

• Pacific Jumping Mouse, Zapus trinotatus. Forest clearings and meadows. 

Erethizontidae: New World Porcupines

• Porcupine, Erethizon dorsatum. Open forest to shrub steppe.

Myocastoridae: Nutrias

• Nutria or coypu, Myocastor coypus. Wetlands. Introduced from South America.

Order Carnivora: Carnivores
Canidae: Canids

• Coyote, Canis latrans. All habitats.
• Gray Wolf, Canis lupus. Forested habitats. May not be in King County at present, but was historically and likely will return in 2020s.
• Red Fox, Vulpes vulpes. Forests and woodlands. Mountains (native populations) and W lowlands (populations introduced from E U.S.).

Ursidae: Bears

• Black Bear, Ursus americanus. Forested and semiopen areas.
• Grizzly Bear, Ursus arctos. Forested and open areas. Would have been present in King County historically; none are currently known to be present.

Procyonidae: Procyonids

• Raccoon, Procyon lotor. Wooded areas, urban and suburban areas. 

Mustelidae: Mustelids

• Marten, Martes americana. Mountain forests, less common in lowlands. 
• Ermine, or short-tailed weasel, Mustela erminea. Forests. 
• Long-tailed Weasel, Mustela frenata. All habitats.
• Mink, Mustela vison. Wetlands.
• Wolverine, Gulo gulo. Forests and meadows. Currently being reintroduced in Washington; presence in King County unknown.
• Western Spotted Skunk, Spilogale gracilis. Woodlands and thickets.
• Striped Skunk, Mephitis mephitis. All habitats except sagebrush, more in open areas than preceding species.
• River Otter, Lontra canadensis, (previously Lutra canadensis) . Marine and freshwater. 

Felidae: Cats

• Cougar Puma concolor,. (previously Felis concolor) All habitats. 
• Lynx rufus, Bobcat. (Previously Felis rufus) All habitats.

Suborder Pinnipedia
Otariidae: Eared Seals

• Steller Sea Lion, Eumetopias jubatus. Large males and sub-adult Steller sea lions can occasionally be seen in the inland waters of Washington State.
• California Sea Lion, Zalophus californianus. Marine, hauling out on floating platforms. Winter visitor, mostly Puget Sound. 

Phocidae: True Seals (also known as Earless Seals)

• Harbor Seal, Phoca vitulina. Marine, hauling out on rocks and sand islands. 

Order Cetacea: Cetaceans (*=Species most likely to be seen)

Eschrichtiidae: Gray Whale

• Gray Whale*, Eschrichtius robustus.

Balaenopteridae: Rorquals

• Minke Whale*, Balaenoptera acutorostrata.
• Humpback Whale*, Megaptera novaeangliae (offshore).

Delphinidae: Dolphins

• Orca or Killer Whale*, Orcinus orca.

Phocoenidae: Porpoises

• Harbor Porpoise*, Phocoena phocoena.
• Dall's Porpoise*, Phocoenoides dalli.

Order Artiodactyla: Even-toed Ungulates
Cervidae: Deer

• Elk, Cervus elaphus. Forested regions.  
• Mule Deer, Odocoileus hemionus. All habitats. "Black-tailed Deer" O. h. columbianus west of Cascades crest.

Bovidae: Bovids

• Mountain Goat, Oreamnos americanus. Alpine and subalpine zone. 

Related Information

• Animals, Plants and Habitat
• Wetlands

Related Agencies

• Department of Natural Resources and Parks
• Water and Land Resources Division