Study of Southampton Island polar bear dens to start this spring

This spring, when polar bear sows and cubs leave their dens on Southampton Island, a research team will gather bits of evidence left behind.

Biotic samples like hair and scat can identify individual bears and their gender. From the scat, scientists can also compose a picture of what the bears have eaten and any contaminants in their system.

Through this, they hope to answer a few questions about the polar bear population in the area and how climate change is affecting the animal’s livelihood.

The idea for this project came from residents of Coral Harbour, which is located in the southern bay of Southampton Island.

“We’ve been talking about this project for two years, so it’s finally got funding and the word is getting out and it’s exciting,” said Leonard Netser, the project lead in Coral Harbour.

Just recently, funding from Crown-Indigenous Relations and Northern Affairs Canada came through that will allow the project to hire about a dozen hunters to take part in the spring survey, gathering the biotic samples.

Already, project BEARWATCH—funded through Genome Canada—is supporting a range-wide genetic study that will include samples collected through this work, also with additional funding for the project through World Wildlife Fund Canada.

The idea of targeting abandoned dens, Netser said, goes back to a time he was out with his son and found six dens along a five-kilometre stretch of a canyon. Each den housed a sow and two cubs. It got him thinking about just how many maternity dens there are on Southampton and how many bears they might contain.

“It’s definitely not the first time I wondered what polar bears did, that goes back a long ways,” said Netser. “I’ve been hunting since I was young … but it was in that one particular creek that we did wonder how many bears are on the island.”

Both male and female polar bears enter dens dug into the snow as soon as it falls, said Netser. “One male bear den I saw was enormous, it was 12 feet high in a glacier,” he said.

Males and females always den separately—the female with her cubs.

Males will leave as soon as the ice is thick enough to walk on, he said, whereas females with cubs will wait until the spring.

“They’re nursing cubs now since November,” said Netser. “Some of them will be abandoning their dens now with tiny little cubs but hopefully most will stay in their dens until closer to April because the weather’s harsh right now.”

If the female doesn’t have a cub, she might, like the males, head out once the ice is thick enough, Netser said.

A question that came up during community information sessions for the project was whether climate change is affecting polar bear denning habits.

“Climate change, it seems to be here. We’re about -16 today when it should be -38,” said Netser. “And it’s been -16 for the last two weeks.”

While there is a lot of talk about melting sea ice and the impact on polar bears, Netser said less is heard about changes in snow conditions. Polar bears require snow for shelter when they give birth.

“That’s something we hope to monitor,” he said. “Climate change is real. We don’t get much snow in the fall anymore and sometimes I wonder if polar bears are giving birth on the ground in exposed areas. With this research we should be able to hopefully keep track of things like that.”

Sample collection for the project requires delicate timing. They have to reach the dens after they’re abandoned and before they’ve caved in and melted away.

“We have to keep our distance from the den when it’s occupied, but for a period of time the mother there will take the cubs out for a walk and return to the den, to get their legs working, gain some strength, that’s how we found those six dens,” he said. “They were just out for a walkabout but went right back to their den when we got in the area.”

In April, he said, an occupied den will have a wide opening, and it’s apparent from the snow that there’s been traffic in and out.

“Otherwise an abandoned den has fresh snow and the entrance is melting,” said Netser. “There are signs of it being abandoned.”

Through this, they’ll also measure snow depths in dens and the dimensions and orientation of the den.

As well as sample collections from the den, they will be setting up structures to snag hair samples from polar bears. These are composed of four poles with barbed wire wrapped around bars in the middle.

The bears have to rub against the barbs to reach bait at the centre. As they do this, the barbs catch tufts of hair, explains Peter van Coeverden de Groot, a research scientist with Queen’s University working on this project.

This is a more challenging method for gathering samples than collecting scat. The structure’s materials must be hauled out by qamatik, pieced together and later taken apart. But hair samples are a much better source of DNA than scat is, said van Coeverden de Groot, who fine-tuned this method through work with his colleagues in Gjoa Haven on the BEARWATCH program.

A bear’s scat “contains the animals it’s eaten if any, then its own DNA, and also a whole suite of bacteria, viruses, and potential parasites,” said van Coeverden de Groot. “There’s a whole soup of DNA in the scat sample. It’s far more difficult to get the polar bear’s identity out of those scat samples, but it’s also the most non-invasive.”

For both the den collections and hair snags, gathering traditional knowledge from elders of Coral Harbour is a critical part of this project.

“It’s important for us to interview elders, and the elders I’m talking about are in their 70s or 80s and they’ve seen a lot,” said Netser.

“That’s how they pass on their knowledge is through their stories. During interviews we hope to get a snapshot of what it was like even before the government came with wildlife regulations and hopefully be able to present the pristine nature where polar bears were not bothered by hunters or climate change.”

Elders will be involved in mapping known denning sites, as well as polar bears’ heavily used routes. That information will be used to decide the locations of hair-snagging structures.

Interviews with elders on this will begin in March, Netser said. The field work should begin in April.

Genotyping and determining the sex and diet of polar bears is a long, complicated process. Van Coeverden de Groot said it would probably be a few months before they have results.

The findings will be reported back to the community, and the pilot project will hopefully inform similar studies in the coming years, as funding allows.

There are plans for students from Coral Harbour’s high school to be involved in the project, which Netser said would help bring back some understanding of polar bears and their denning habits that has diminished through generations who have less experience on the land.

“We want to make them aware that polar bears do den up, they are physically here with us on the island,” he said. “We probably drive right by them but because they’re deep in the snow, there’s no apparent bear. They could be a few feet from us and we wouldn’t know.”