Sat. Mar 2nd, 2024
Winter Ticks and Hairless Moose

Every year, Algonquin Provincial Park biologists hear this question from at least one park visitor: “Why did the moose I saw have bald spots?”

In a bad year, there will be many inquiries.

What is the cause for hair loss?

This hair loss is caused by winter tick infestations. Dermacentor albipictuswhich causes the moose to itch a lot and continuously lick and groom themselves to the point of losing their hair.

In addition to being incredibly annoying to moose, these itchy bloodsuckers also put moose at risk of dying from exposure to the elements through hypothermia.

An isolated moose among some bare trees.

Winter tick larvae (or moose ticks) attach to moose in early fall during mating season, when moose are on the move. The larvae are on the vegetation, waiting (also called searching), with their hooks extended for a warm elk to pass by.

Winter tick.

They remain on the elk during the winter and begin to feed on the elk’s blood. In spring, adult female ticks swell to the size of a grape, engorged with blood after months of blood meals.

A moose calf with a high load of female ticks can lose about half of its total blood volume in two to four weeks. Some moose can harbor up to 15,000 of these ticks at a time.

Blood loss, combined with hair loss, can lead to rapid weight loss, depletion of fat stores, and hypothermia, putting moose at risk of not surviving the winter.

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Should we try to help?

Although unpleasant to witness, the winter tick is a natural parasite of moose. He dermacentor albipictus He has been hitchhiking in the forests of Canada on the back of elk for centuries.

cow moose in the lake

That being said, moose are an important part of the Algonquin ecosystem and over the years, significant moose deaths have been associated with the moose tick.

There is a lot we still don’t know about the winter tick and its relationship with moose. There is a correlation between climate and tick abundance: more ticks are present in years with a warm fall and early spring. This relationship may become more pronounced with changes in weather patterns.

While the impact of ticks is not enough to eliminate Algonquin moose, they can have a very real impact on the moose population and this potentially influences future park planning.

Since 1984, Algonquin Provincial Park biologists have been conducting aerial surveys in the spring to assess the extent of moose hair loss.

Helicopter in the sky.

“By conducting studies like these, we can increase our understanding of the influence of winter ticks on the moose population in the park,” says Algonquin biologist Jennifer Hoare. “We can also share the information with other jurisdictions that have moose populations affected by the winter tick.”

Do you want to get involved?

Several provinces and states in Canada and the northern United States have become increasingly interested in monitoring winter ticks and the relationship to moose populations, as several of these areas are experiencing declines in moose numbers.

You can help by reporting your observations of winter ticks through iNaturalist (learn more about iNaturalist). Simply take a photo of the moose, identify or tag your photo “winter tick,” and describe the amount and areas of hair loss.

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You can also document wintering ticks observed on the ground, for example in a moose bed. These observations help biologists determine the timing, distribution, and levels of wintering ticks over a given time period.

At Algonquin Provincial Park, you can also report your observations to park staff. Just remember: As alarming as it may be to see, hair loss in moose is a natural phenomenon.

(Park users should be assured that the moose tick is rarely a problem for humans. However, normal precautions should be taken when walking in the woods.)