Global warming, inbreeding threaten Nunavut muskoxen

MONTREAL — While the numbers of muskoxen roaming Nunavut’s High Arctic islands are on the rise, these huge animals face an uncertain future.

With their keen eyesight, cozy fur and shovel-like hooves, the “umingmait” or “animals with skin like a beard” have adapted extremely well to life in the frigid polar desert. For more than 90,000 years, they’ve lived in the High Arctic, where they survived the last Ice Age on protected, ice-free Banks Island.

But now this habitat is warming up, and higher temperatures may spell big trouble ahead for the lumbering animals.

“They’re doing very well now. They’re a roaring success and they’re going all over the place, but the game is changing,” said Peter de Groot, a researcher studying muskox populations on the High Arctic islands.

Other Arctic animals, such as the polar bear and Peary caribou, are also under stress as a result of warming temperatures. But because the numbers of muskox are large and the herd is stable, they’re much easier subjects to study.

According to de Groot, muskoxen also provide an ideal kind of “window” to understand what is happening to other populations of animals such as rhinos, elephants and pandas, who lived in protected and unchanging habitats for millennia, and are now mainly confined to zoos.

For the past five years, De Groot and Peter Boag, a biology professor at Queen’s University in Kingston, Ontario, have been collecting and analyzing tissue samples from muskox carcasses.

De Groot spent his summers combing Banks Island and Ellesmere Island, gathering tissue samples from dead muskox, while hunters also contributed samples from their kills to his study.

Laboratory analysis of these samples showed that the 75,000 muskox in the High Arctic islands are highly inbred. Genetic testing of 72 animals — similar to that done in paternity cases — showed seven had nearly identical DNA.

De Groot and Boag have concluded that, as a population, these muskox likely suffer from what’s called “inbreeding depression.” This means that there’s a lack of fitness in the herd, a result of too much mating between related animals.

Lack of genetic variation gives muskoxen, in de Groot’s words, “a lousy defense” against any new elements in their environment. It could weaken their immune system, making muskoxen less able to fight off new illnesses, which are expected to spread into the High Arctic as temperatures rise.

But this is just a small part of the challenge that lies ahead for muskoxen.

Muskox prefer the grazing conditions of the polar desert, with its thin, windblown snow layers and cold temperatures. There they subsist on grasses and low-lying willows, vegetation common to the High Arctic, and calve between April and June in temperatures of -30 C. They have few natural predators.

Accustomed to dry, solid ground, with a light snow cover, muskoxen have never thrived on Baffin Island, said de Groot, because it’s too wet and warm.

The muskox population on the High Arctic Islands is likely on the rise because slightly warmer conditions now are increasing the animals’ food supplies, but if temperatures go up too much, this environment will begin to change in other, less beneficial ways to the animals.

Muskox will then have to adapt to the new conditions or risk dying out.

And the researchers caution that muskox may not be the only casualties of a changing climate.

“It’s a call saying, ‘let’s look at global warming in a real sense’,” de Groot said. “We have to spend money and time to see what will happen.”