The Pacific Northwest (PNW) typically encompasses Washington, Oregon, and British Columbia, sometimes extending into parts of Idaho and Alaska. This region features a dramatic collision of environments, from temperate rainforests and jagged mountain peaks to drier high desert plateaus inland. This varied geography creates a mosaic of habitats, supporting an exceptionally rich biodiversity that defines the wildlife of the PNW.
Large Terrestrial Mammals and Apex Predators
The dense forests and high alpine meadows of the PNW are home to North America’s most recognizable large mammals and powerful apex predators. The Roosevelt Elk (Cervus elaphus roosevelti), the largest subspecies of elk, is a prominent herbivore found in the coastal rainforests west of the Cascades. Adult bulls can weigh up to 1,200 pounds and thrive in areas with meadows and forest openings, which provide ample forage, while older forests offer necessary shelter from heavy rain and snow.
The North American Black Bear (Ursus americanus) is widely distributed throughout the forested regions. Their coloration can range from black to cinnamon or brown, and they are highly adaptable omnivores, with a diet primarily consisting of vegetation, berries, and fish. In contrast, the Grizzly Bear (Ursus arctos horribilis) population in the North Cascades is critically imperiled, with estimates suggesting fewer than ten bears remain, primarily in the remote transboundary area with British Columbia.
The Grey Wolf (Canis lupus) has been successfully re-establishing populations in the PNW after decades of absence. Wolves function as a keystone species, altering the behavior and distribution of prey like elk and deer. This re-colonization has led to complex interactions with the region’s other top predator, the Cougar (Puma concolor), which is widespread across the mountainous terrain. Wolves are often the dominant competitor, displacing cougars from their kills and altering their foraging patterns to higher elevations.
Another large ungulate, the Moose (Alces alces), is increasingly found in the North Cascades and eastern portions of Washington and British Columbia. These large browsers prefer riparian areas and wetlands, feeding heavily on aquatic plants and deciduous growth like willow and aspen.
Iconic Pacific Marine and Aquatic Life
The Pacific Ocean and its major river systems, including the Columbia and Fraser, support a wealth of specialized marine and aquatic life. The Pacific Salmon are anadromous fish, meaning they hatch in freshwater, migrate to the ocean to grow, and return to their natal streams to spawn and die. Five species of Pacific Salmon—Chinook, Coho, Chum, Sockeye, and Pink—are found in the region’s waterways.
The Orca (Orcinus orca) is the apex marine predator of the PNW, with two distinct ecotypes frequenting the Salish Sea. The endangered Southern Resident Orcas are fish-eaters, specializing almost exclusively on Chinook salmon. Alternatively, the Transient Orcas (also known as Bigg’s Killer Whales) are mammal-eaters, hunting seals, sea lions, and porpoises.
The coastal waters and river mouths are also populated by various pinnipeds, including seals and sea lions. The Steller Sea Lion (Eumetopias jubatus) congregates on offshore rocks and islands along the coast. California Sea Lions (Zalophus californianus) and Harbor Seals (Phoca vitulina) are highly adaptable, often found far up major river systems like the Columbia, where they haul out on docks and jetties.
Essential Forest and Canopy Dwellers
The dense, wet, old-growth coniferous forests of the PNW provide habitat for a variety of smaller, specialized species. The Marbled Murrelet (Brachyramphus marmoratus) is a unique seabird that nests high on the moss-covered, large branches of old-growth conifers. It forages for small fish in the marine environment.
The Northern Spotted Owl (Strix occidentalis caurina) relies on mature forests with large trees for nesting and roosting. This owl is currently threatened by habitat loss and by competitive displacement from the invasive Barred Owl, which is expanding its range westward. The Pacific Tree Frog (Pseudacris regilla) is common across a wide range of habitats, from sea level to high elevations.
Among the smaller mammals, the Pacific Marten (Martes caurina) is an agile, arboreal predator found in high-elevation coniferous forests. Martens are omnivorous, consuming small mammals, birds, and berries. The Douglas Squirrel (Tamiasciurus douglasii) is a highly vocal, small rodent that lives in conifer forests, subsisting mainly on the seeds of cones. Finally, the Common Garter Snake (Thamnophis sirtalis) is frequently encountered in moist, grassy areas near water.