Climate change threatens hairy survivor of multiple ice ages

Muskox lived alongside mammoths during the ice age and thousands still roam in the Northwest Territories today.

But the number has dwindled from what it once was. 

"When you consider how many ice ages they survived, I think we're lucky that we still have them with us," said Jan Adamczewski, ungulate biologist for Environment and Natural Resources with the N.W.T. government.

Scientists are uncertain how well the cold-adapted species will manage as temperature rise around the globe.  

"I think in some ways they're quite vulnerable that way," he said.

Widespread death seen during N.W.T. summers

Muskox on Banks Island in the northern reaches of the N.W.T. have experienced wide scale die-offs the past decade. It's believed bacteria is a big contributor.

"These may be perfectly healthy muskox. In good shape, lots of fat," Adamczewski said.

"They just kind of show up as dead on the landscape."

As the temperatures continue to warm, it's possible these bacterial outbreaks could persist and become more frequent. 

"We are quite concerned about where this is going to go in the future."

In the 1990s, there were 70,000 muskox on Banks Island. In 2010 there was about 37,000 and in 2014 there were just 14,000.

Rain in the winter renders food inaccessible 

The effects of climate change on muskox are apparent, said Joel Berger, scientist with the Wildlife Conservation Society and a professor at Colorado State University.

"Whether they be parasites, whether they be disease, whether they see juvenile stunting which is the consequence of rain on snow events — it's not good," Berger said.

He's studied the mammal for ten years and coauthored a paper titled "Climate Degradation and Extreme Icing Events Constrain Life in Cold-Adapted Mammals" that was made public Thursday: "We didn't target our work to look at direct climate effects but across the last ten years it's become so obvious."

The warming weather has brought rain in months where there typically hasn't been any in arctic areas. Muskox are ruminants who rely on plant material to survive and tend to stay in one place during the cold season. 

"Rain on snow, ice layers — we know that's bad news." Adamczewski said.

The ice layers prevent the muskox from reaching their food source.

"If the females can't access food because it's frozen under a layer of ice, they have a hard time," Berger said. 

The newborn muskox were smaller in size in areas that experienced rain on snow, his research found. 

It's unclear what the long term implications of this are, but the research suggests the undernourished calves could die or may not reproduce. 

Looking forward

The situation isn't totally dire, according to the scientists. 

Anecdotes from the Sahtu region suggest there has been population growth in the area, Adamczewski said, adding there have been reputable reports of muskox beyond the tundra near the Saskatchewan and Alberta borders. 

He also noted that the mainland population of muskox was extremely low around the 1900s but with government protections in place, it grew again. 

"The geographical range of the animal has grown. All of their mainland range — [it's] certainly something of a success story."

However, he said the numbers were also quite low on the island during that time, even though there wasn't widespread fur harvesting there. 

"You kind of wonder, could that happen again. Especially if they're vulnerable to climate events and changing weather patterns, so it is quite worrisome."