The role of wolves in ecosystems

Gray wolves are an apex species that occupy a top niche in the natural food chain. Like bears and cougars, they have few competitors and play a prominent role in any ecosystem they inhabit.

Competition and prey

Wolves primarily prey on elk, deer, moose, and other ungulates, although they also feed on smaller species such as beaver, mice, squirrels, rabbits, muskrats, marmots, grouse, and even songbirds.

They may also compete with other top carnivores such as cougars, bears, and coyotes. Studies in other areas have shown that the presence of wolves can reduce coyote populations.

In these and other ways, wolves can influence the dynamics of wildlife species across an entire ecosystem, altering predator-prey relationships and even the natural landscape. While they may affect abundance in some species, wolves can also play an important role in the environment.

In ungulate herds that have not been exposed to wolves for a time, this can increase the proportion of healthy animals of prime age, leading to higher pregnancy and birth rates.

Wolves usually hunt in packs averaging about five individuals, but up to 15 have been observed in Washington. They chase their prey across relatively open landscapes. Packs are highly territorial, with an average home range of 140 to 400 miles.

State wildlife managers have found no evidence that wolves’ current predation levels have had a discernible effect on Washington’s elk, deer, or moose populations, most of which are growing or stable. WDFW monitors the status and trend of ungulate populations in Washington and provides regular updates. WDFW is also partnering with University of Washington grad students on the Washington Predator-Prey Project, a 5-year effort to investigate the effects of wolves and their competitors on ungulate populations in managed landscapes. This video explains the science behind the study.

Some western states have found that high concentrations of wolves can hasten the decline of some herds, especially those impacted by other factors such as harsh weather, poor habitat, high hunter harvest, and other predators such as cougars and bears.

As Washington’s wolf population continues to grow, WDFW has expanded monitoring efforts to help understand the effect of wolf predation on state herds. See the 2015-2017 ungulate assessment for more information.

The state’s wolf conservation and management plan provides WDFW with several options to protect at-risk ungulate populations from predation by wolves.

Other carnivores

Throughout North America, wolves have shared habitat with cougars, bears, coyotes, and other carnivores for centuries, often competing for the same prey. Most of their interactions take place at kill sites, where wolves usually have the advantage because of their pack behavior.

Cougars and wolves rely on the same main food sources, but have different hunting techniques. Wolves are coursing predators, running prey down, usually in packs. Cougars are stalking predators, ambushing prey as solitary hunters.

Reports from Yellowstone National Park and elsewhere suggest that cougars may avoid areas used by wolves or focus on different prey to avoid encounters with packs. This is also true for black bears, although grizzly bears usually prevail over wolves in a fight over a carcass.

Recent studies have found that the coyote population in Yellowstone National Park has dropped 39 percent since wolves were reintroduced in 1995. Grand Teton National Park reported a 33 percent reduction in coyotes. Less clear is whether wolves would have the same effect outside of national parks.

While wolves are highly protective of their kill, many other carnivores and scavengers benefit from the carcasses they leave behind. These carcasses may help to sustain large carnivores, wolverines, foxes, fishers, martens, raccoons, eagles, ravens, and magpies, especially during winter.


By changing the dynamics of other wildlife species, wolves can also affect the vegetation and other characteristics of natural landscapes. While there are few examples in Washington, land once overgrazed by deer, elk, and other herbivores recovered once wolves returned to the area.

After wolves were removed from Yellowstone Park in the early part of the last century, the problem of overgrazing became so acute that herds of elk, pronghorn, and bison were culled to protect the remaining vegetation. Since 1995, when wolves were reintroduced to the park, there has been resurgence of woody browse species in some areas such as willow and aspen.

Some scientists have suggested that a similar situation may exist in Olympic National Park, where extensive browsing by elk may have caused substantial changes in riparian plant communities. This, in turn, has been linked to riverbank erosion and channel widening, which reduce rearing habitat for salmon, steelhead, and resident fish.

These examples may not be evident on a large scale across Washington because deer and elk population management methods differ from national parks. However, they may help illustrate the prominent role wolves can play in nature.