Ticks and itches lead to moose hair loss

The iconic Canadian moose is the largest mammal to roam in Algonquin Provincial Park and thousands of park visitors delight in spotting them every year. 

Yet did you know these majestic animals are sometimes under attack by a blood-sucking parasite the size of a grain of quinoa?  Multiply these voracious vampires by the thousands on a single moose and you have relentless grooming that causes some moose to lose their hair and increase their risk of dying from hypothermia. 

So what causes this maddening and potentially lethal infestation?

Engorged tick found at moose bedding area.

 Moose, or winter ticks. The Dermacentor albipictus, or winter tick, attaches itself as larvae in early fall during mating season when moose are on the move. In spring, the adult females swell to the size of a grape, engorged with blood after months of blood meals.  Some moose can host as many as 15,000 of these ticks at once.

 Warmer temperatures.  Winter ticks thrive in the winters that follow a year with an early spring and mild fall.   Climate change may impact infestations, if we encounter warmer spring temperatures and less snow in the future.


 Excessive grooming.  To cope with the infuriating infestation, moose will aggressively groom themselves, scratch with their hind hooves or rub furiously against trees to relieve the irritation, all to the point of wearing away their luxurious coats.  Coupled with blood loss, this can cause reduced physical fitness, growth and fat stores, all of which can put moose at greater risk for hypothermia or even death in colder winters. 

Moose photogaphed in Algonquin with moderate hairloss. (Photo Credit: Ian Shanahan)

  Natural phenomenon.  As disturbing as it is, the winter tick is a natural parasite for moose and one of many that attach themselves to the animals every year.  The Dermacentor albipictus has been hitching rides on moose in the forests of Canada for centuries. 

 Mysterious relationship.  Ultimately, the relationship between ticks and moose is not fully understood.  Every spring since 1984, biologists at Algonquin Provincial Park have been conducting aerial surveys of tick infestation based on the degree of hair loss in moose. This allows staff to predict the potential impact on the local moose population.  In 2014, 64 moose were assessed with an overall rating that was fairly low for hair loss meaning moose deaths due to winter ticks are not anticipated in Algonquin this year.

 Why should we care?  Moose are an important part of the Algonquin ecosystem and significant die-offs of moose have been associated with the moose tick over the years.  1999 was the most recent and significant die-off of moose due to winter tick.   While the impact from ticks is not enough to eliminate moose from Algonquin, they can have a very real impact on the moose population and this potentially influences future planning at the park.  

“Ontario Parks really cares about ecological integrity,” says Algonquin’s Park Biologist Jennifer Hoare. “It’s part of our legislation. We want to have all of the components, processes and natural disturbances going on in an ecosystem left intact as much as possible, including the natural relationship between moose and ticks.  By doing the annual aerial surveys every year, we can monitor the problem, assess the hair loss severity index every year and better understand our populations. 

The Moose Hair Loss Survey helps park staff to monitor and assess the health of the Algonquin moose population.

 “If we do conduct management planning that could affect our moose population, we will know that much more about it and be able to make wise decisions that will ensure we can maintain these species and their natural interaction with moose ticks within Algonquin.”

If you see a moose with bald patches inside the park, simply report it to park staff.  Your information will help science staff assess the health of the moose herd.  Just remember, as alarming as it may be to see, hair loss on moose is a natural phenomenon.

For more information about the Moose Hair Loss Survey, visit the Friends of Algonquin Park website.

Park users should be reassured that the moose tick is rarely a problem for humans.  However normal precautions should be taken when you are walking in the woods.