Wolves

Wolf in winter

NPS

The gray wolf (Canis lupus), also known as the timber wolf, has been the prevailing predator of Isle Royale National Park since its arrival to the island in the late 1940s.

Characteristics

The gray wolf gets its name from the thick, gray fur coat covering its body. While most wolves are gray, their coats can range in color from reddish to solid black. On average, adult wolves are five to six feet in length, with females weighing 50-85 pounds and males weighing 70-110 pounds. A wolf will hunt small prey such as snowshoe hare and beaver, however, they often live in small packs of four to eight members and work together hunting larger prey like moose.

Wolf Population

It is largely accepted that wolves arrived on Isle Royale by crossing an ice bridge that formed between the island and the Canadian mainland during the winter of 1948. Since this initial population of island wolves, the population has varied from 50 animals in 1980 to a low of two animals between 2016 and 2018. Wolf population variation is driven by the availability of its primary food source of older moose and calves, and the spread of canine diseases to the island. Furthermore, genetic inbreeding has led to physical deformities and has, at times, resulted in low productivity and survival.

 

A graph showing the number of wolves and number of moose on Isle Royale since 1980.

NPS

Wolf & Moose Population

The prey to predator relationship of Isle Royale's moose and wolves has a direct effect on both species' populations. Wolves help stabilize the moose herd by preying on the old, young, injured and ill. Strong moose numbers allow for stable winter hunting for the wolves. Check out the correlation between wolf and moose populations of Isle Royale since 1980.

Where Are The Wolves?

Isle Royale wolves can be found throughout the island. They are very elusive, but your best chance of seeing them would be along lakeshores, open areas, or hiking trails.

 

Wolf with pups

NPS

Breeding

In the hierarchy of wolf packs, there is typically one dominant female who breeds with the dominant male. A female wolf can breed by the age of two. Breeding occurs in February and March with pups born in April and May. A typical litter consists of four to seven pups, which will remain in the den for their first six to eight weeks.

Safety in a Wolf Sanctuary

Wolves are usually wary of people and will leave an area when they hear or smell humans. Help keep yourself and Isle Royale wolves safe by following these guidelines:

• Do not provide food directly or indirectly. Stow your food properly to limit the smell and do not leave food or garbage in campsites or picnic areas. Dispose of fish remains in water that is at least 50 feet deep or at least 200 feet from campgrounds, water sources, and trails.

• If you meet a wolf at close range (less than 25 feet) and it does not leave or is advancing, do what you can to terminate the encounter. Back away or make noise, but do not run away. If you observe them at more than 25 feet, leave the area but do not run.

• If a wolf appears to show unusual behavior, such as lack of fear of humans, please report your sighting to park staff.

• If you come upon a dead moose, keep moving away from the carcass. Wolves may be present and will be more aggressive to protect the food source. Let park staff know the location of the carcass.

• No pets are allowed on the island. Wolves are territorial and will view a domestic canine as a threat. Domestic dogs can also spread canine diseases like parvovirus and distemper, which are deadly to wolves.

 

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  Beaver

  Beaver create important aquatic habitat for other island creatures.

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  Moose

  Moose are the largest mammal on Isle Royale.

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  Wolf Reports

  Read about the ongoing efforts to augment the wolf population of Isle Royale.

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  Predator-Prey Relationships

  Wolves, moose, and beavers play important roles in Isle Royale's ecosystem.

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  Why Relocate Wolves?

  Wolves have been a part of the island's wilderness for decades, so why relocate?

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  Wolf Relocation

  Nineteen wolves were relocated to Isle Royale from the Great Lakes Region.