Montana Public Radio

Bug Bytes: Winter Tick And Moose

Jun 12, 2020

If you spend lots of time in the great outdoors, at one point or another you’ve likely encountered a tick. Certainly not the kind of animal encounter you we’re hoping for.

Aside from the unappealing thought of these creepy arachnids burrowing into your skin for a blood meal, in certain parts of the country different tick species can cause significant problems with the transmission of Lyme disease, Rocky Mountain spotted fever or other diseases.

But there’s another species of tick that largely goes unnoticed by humans – the winter tick…also known as the moose tick.

An adult female winter tick.
Credit Griffin Dill / University of Maine Cooperative Extension

Unlike other ticks which feed on two or more hosts in their lives, the winter tick remains on a single host its entire life. And as you might guess, its most common hosts are moose.

While a tiny tick may seem like a trivial nuisance to an animal weighing up to 1,000 pounds or more, what they lack for in size, they make up for in numbers.

Over the past decades, the number of winter ticks has been increasing across the northern states. Warmer fall temperatures and earlier spring snowmelt improves conditions for winter ticks to thrive.

The result? Individual moose have been found with up to 150,000 ticks.

At these numbers, the ticks cause hair loss as the moose scratch to remove them. This increased activity and disruption from time spent feeding results in loss of critical fat reserves for winter survival. And in extreme cases, moose can literally be bled to death, dying from anemia.

In a world of increasing change, new and growing issues will continue to emerge as species either take advantage of or try to cope with shifting conditions.