By: Jodie Provost, DNR Private Land Habitat Coordinator
Gray wolves have a unique legacy and saga in Minnesota. Through the ups and downs, the majority of Minnesotans have valued this Northwoods icon as ecologically important, scientifically fascinating, aesthetically attractive, recreationally appealing and significant for future generations. Wolves inhabited most of North America north of 20 degrees latitude prior to European settlement, but due to human persecution, habitat deterioration, and reduction of prey populations, they declined dramatically in the lower 48 states. In the 1950s, the Minnesota wolf population was estimated between 300 to 600 animals. By the 1960s, the only population of wolves left in the lower 48 was in our state’s northern forest and on Isle Royale National Park. In 1974, wolves in Minnesota were afforded full protection as endangered under the federal Endangered Species Act (ESA), making it illegal to kill them except in defense of human life.
Threatened or not? Protections provided under the ESA, along with a rebounding deer population, allowed remaining wolves to flourish and repopulate northern Wisconsin and Michigan’s Upper Peninsula. In 1978, wolves were re-classified as federally threatened in Minnesota, allowing the federal government to control wolves in response to livestock depredation. In January 2012, wolves in the western Great Lakes populations were completely removed from the federal Endangered Species List, allowing states to manage them. Minnesota then began annual harvests in 2012-14. However, in December 2014, a federal judge returned federal protection for wolves in Minnesota, Wisconsin and Michigan, reversing it to a federally threatened status in Minnesota and endangered elsewhere in the Great Lakes Region.
Current Status Since the late 1970’s, Minnesota has monitored its wolf population regularly using estimated amount of land area occupied by wolf packs (from wolf sign observations collected by state, federal, tribal, county and forestry industry cooperators while conducting normal work duties over winter), average territory size, and average mid-winter pack size (both collected from radio-collared wolves). The current population estimate is 2,221 wolves and 374 packs in an occupied land area of 27,251 square miles. The 2001 Minnesota Wolf Management Plan, utilized when the wolf is delisted and the state has management authority, notes a minimum population goal of at least 1,600.
Heat Pads Gray wolves are one of four native canids in our state. They vary in color from gray, black, buff with reddish coloring and even white. Females weigh 50 to 85 pounds and males 70 to 110 pounds. They stand 26-32 inches tall at the shoulder and leave tracks averaging 4.5 inches long. Their adaptations include long legs for a mobile lifestyle, and thick undercoats of winter fur and paws with webs of tiny blood vessels on the bottom to act as ”heating pads” for frigid cold. As habitat generalists, they thrive in any habitat provided prey is abundant and human-caused mortality is controlled.
Pack Life Highly social creatures, wolves form packs, a related group of wolves consisting of a mated male and female and their offspring. Typically, only the mated male and female pair breeds. Breeding occurs from February to March with four to seven pups born in a den in April and May. After six to eight weeks, pups are moved to rendezvous sites used by the pack throughout summer. By September or October, pups are ready to join the adults. At one to two years old, they disperse from their pack, often 50 to 100 miles, but up to 550 miles. Successful breeders commonly live six to eight years in the wild, but up to thirteen years is possible. Non-human causes of mortality include starvation, death from conflicts with other wolves, diseases such as mange and canine parvovirus, and injuries from prey animals. Human causes of mortality include legal depredation control, illegal poaching, and accidental causes.
Mile Maker Wolf pack and territory sizes are highly variable. Data from radio-collared wolves in Minnesota in winter 2014-15 reflected an average pack size of 5.1 wolves (range of 2 to 13) and average territory size of 73 square miles (range of 10 to 277). Territory size is often affected by prey density. Primary prey are deer and moose. Many miles are put on over their large territories, up to 30 per day, to find and kill the 15 to 20 adult-sized deer per wolf per year they require to sustain their pack. Secondary prey are beaver and snowshoe hare. Most activity occurs at dusk and night.
Role Player Wolves have an important niche to play in our ecosystems. In Minnesota, wolf and white-tailed deer populations are closely linked, strongly influencing each other. Interactions between them are affected by factors such as individual densities, sex and age structures, human-related activities (e.g., hunting, poaching, dogs, timber harvesting, road development, supplemental feeding), winter severity, presence of alternate prey, and habitat quality.
Wolves directly impact white-tailed deer populations as their main cause of natural mortality. The most vulnerable individuals are newborn fawns, and generally fawns and older adults during winter. Because of this, much of the wolf predation on deer is likely “compensatory”, meaning that many of the individual deer wolves remove were unlikely to survive the year anyway. Wolves also have less obvious effects on deer, such as affecting their habitat use and behavior. For example, deer may avoid high-risk areas, be forced to move around the landscape more, and be more vigilant or wary in landscapes where wolves are present.
In MN, wolves are generally not the sole, nor often even the key, contributor to prey population declines, but their impact in combination with other factors can contribute to deer population declines. If deer habitat quality is reasonably good, any wolf-related effects are likely to be small-scale and short-lived. Their impact varies with circumstances such as winter conditions, deer habitat quality, and/or hunter harvest. Increases in annual deer harvests in much of Minnesota wolf range during the early to mid-2000’s, when the wolf population was at its highest estimate (about 3,000), indicate that wolves’ effect on deer harvests is minimal.
Because deer are the wolf’s primary food across most of their Minnesota range, it is easy to understand the outcome for wolves when deer populations decline. In the last three years, wolf population estimates have been 2,200 to 2,400, while deer harvest has been its lowest since the mid to late 1990’s. This type of predator-prey relationship—a decline of its prey population, followed by a lag period and subsequent decline in the predator population—is classical, but it is not simple. As mentioned above, many other factors influence the dynamics of the relationship. In areas where multiple large ungulate prey exist (e.g., deer and moose), predator-prey dynamics can even be more complex.
Challenges While the rebounded wolf population is an ecological success story, it creates challenges for farmers, ranchers and rural residents who must protect livestock and pets. To prevent conflict, appropriate animal husbandry and deterrents are encouraged and depredating wolves removed when needed. Helpful practices include maintaining healthy, well-fed livestock, keeping lame, sick, birthing or newborn animals in a safe area, using guard animals, keeping pastures free of brush, and keeping pets close to home and bringing them in at night.
If depredation occurs, evidence should be preserved and the incident reported to a DNR conservation officer within 24 hours. Because wolves are currently protected under federal law, it is illegal to harm or kill them, except in defense of human life. Attempts to frighten away wolves must be done without harming them. If a wolf kill is verified, a government trapper is contacted and compensation made.
Preventing Mishaps Wolves are typically “shy” and avoid people. However like any large predator, such as bear or cougar, they are capable of adapting to human activity, losing fear of humans, and posing risk to people. Rare, but well-documented accounts of wild wolves attacking people in North America do exist. Accounts of wolves killing people persist in India, Russia and central Asia. Attacks can often be attributed to loss of fear of people, especially if they associate humans with providing food. Never encourage a wolf to approach or not fear you.
While your risk of being struck by lightning is greater than being attacked by a wolf, outdoor enthusiasts in wolf range should take precautions to prevent mishaps. Do not cook near your sleeping area, keep the site and utensils clean, properly disposing of food and garbage, and keep pets near and their food contained. In the rare event you do encounter an aggressive wolf, don’t run. Face and stare at it. If it approaches, aggressively step toward it, yelling or clapping your hands. If with a companion and more than one wolf is present, place yourselves back to back. Retreat slowly. If attacked, stand your ground, fight with any means, make noise and climb a tree if needed.
The Future For now, the wolf population appears secure in Minnesota. To ensure their role in our ecosystems, our heritage, and in recreation, management of human-wolf interaction will be key, especially as our human population continues to increase, spread across the landscape and impact habitat and key wolf prey. For more information on wolves, see the Minnesota DNR wolf management web page. Much thanks to Dan Stark, DNR wolf specialist, and John Erb, DNR furbearer specialist, for their expertise in developing this article.