Wolf packs once freely roamed North America from the Arctic tundra to Mexico but extermination programs and loss of habitat led their populations and home ranges to dwindle to near demise by the early 1900s. The U.S. Fish and Wildlife Service listed the Northern Rocky Mountain Wolf as an endangered species in 1973 and designated Greater Yellowstone Ecosystem as one of three recovery areas.
Form 1995 to 1997, 41 wild wolves from Canada and northwest Montana were released in Yellowstone National Park. Since then Yellowstone’s wolf numbers have fluctuated between 83 and 123 wolves since 2009. As of January 2024, there are at least 124 wolves in the park.
Yellowstone’s wolves live in packs with 10 distinct packs living inside the park’s boundaries. The size of these pack depends on abundance of prey with an average size of 11.8 individuals. During the winter, 90% of the wolves prey is elk but they are also feed on bison. The majority of winter bison consumption comes from bison dying from injuries sustained during breeding season.
While an individual wolf has practically no chance of killing a healthy adult bison, when cooperative hunting strategies are employed by a coordinated group they are more than capable of preying on the largest land mammal in North America. The following video comes from road to Mammoth Hot Springs in Yellowstone. A motorist slowed down as a herd of bison approached his vehicle and was surprised to see what was on their heels.
While an individual wolf has practically no chance of killing a healthy adult bison, when cooperative hunting strategies are employed by a coordinated group wolves are more than capable of preying on the largest land mammal in North America.
Yellowstone Wolf Safety Guidelines:
Wolves are not normally a danger to humans, unless humans habituate them by providing them with food. No wolf has attacked a human in Yellowstone, but a few attacks have occurred in other places.
Like coyotes, wolves can quickly learn to associate campgrounds, picnic areas, and roads with food. This can lead to aggressive behavior toward humans.
What You Can Do
- Never feed a wolf or any other wildlife. Do not leave food or garbage outside unattended. Make sure the door is shut on a garbage can or dumpster after you deposit a bag of trash.
- Treat wolves with the same respect you give any other wild animal. If you see a wolf, do not approach it.
- Never leave small children unattended.
- If you have a dog, keep it leashed.
- If you are concerned about a wolf—it’s too close, or is not showing sufficient fear of humans— do not run. Stop, stand tall, and watch what the wolf does. If it approaches, wave your arms, yell, flare your jacket. If it continues, throw something at it or use bear pepper spray. Group up with other people, and continue waving and yelling.
- Report the presence of wolves near developed areas or any wolf behaving strangely.
Wolves in Yellowstone occasionally become habituated to human or vehicle noise. Biologists successfully aversive-condition several wolves each year. Visitor education is important to help keep wolves wild and wary of humans. There have been no cases of people injured by wolves in Yellowstone; however, two have been killed (2009 and 2011) when their behavior could not be changed with aversive conditioning. Both wolves were likely fed by people.
