The bear facts

MIRIAM HILL

“What do you think this is?” Jackie Bourgeois asks, holding what appears to be a large leg bone, maybe two and a half feet long.

“It’s the baculum from a walrus,” she says, enjoying the shock she has caused. Baculum is the scientific term for penis bone.

“It’d be a good baseball bat if it were a bit longer,” she says, holding the narrow end and swinging it slightly.

Bourgeois is a laboratory technician at the polar bear lab in Iqaluit. She appears quite comfortable surrounded by bones, teeth and scientific equipment. It’s Friday afternoon and the wildlife office is fairly quiet.

She takes a number of white plastic disks from the counter and sets them in the sink so clean water can run over them. The disks contain polar bear teeth in the process of being decalcified, she explains. Removing the calcium makes it easier to slice cross sections from the teeth to determine the bear’s age.

What have the bears been eating?

By law, all hunters in Nunavut must turn in the jaw of every bear they harvest, as well as the baculum. The wildlife office pays $35 for the jaw and $30 for the penis bone. It also offers cash for other optional samples — $95 each for ear tags, lip tattoo, rump fat, liver, skin and hair.

“In different areas we ask for different things. For example, right now we’re collecting skin and hair from the Foxe Basin and the Davis Strait population,” she says. The samples are being used to determine what contaminants may be affecting the animals in those areas.

Officers are also studying liver and fat samples from a variety of populations. The fat is examined to determine the effects of contaminants, and is also being sent to Dalhousie University in Halifax for fatty acid studies.

“They look at the fatty acid layers to see what the bears are eating,” Bourgeois explains. Every animal has it own distinctive fatty acid signature.

“So if they’re eating ringed seal, if they’re eating harp seal, walrus or whatever, [researchers] can look through the fat and say, ‘Oh, that’s what the bear’s been eating.’”

How old is it?

The lower jaw is collected not only for tissue samples, but for the teeth. As bears age they do a lot of chewing, but the teeth are kept in place by layers of a substance called cementum, which forms on the outside of the teeth. It’s the layers of cementum that researchers count to determine a bear’s age.

“Over a period of a year, they will basically grow a layer of teeth,” Bourgeois says.

She demonstrates the process of slicing ultra-thin cross sections from the tooth using a machine called a cryostat. A series of sections is mounted on a microscope slide to be stained so that the rings can be counted.

Because the polar bear harvest in Nunavut works on a flexible quota system, the department must study all bears killed during the year. Polar bear hide tags are allocated based on harvest reports from the previous year.

This year the Davis Strait region, which includes the communities of Iqaluit, Kimmirut and Pangnirtung, has a quota of 32. Iqaluit’s quota is 12 males and six females. The department asks hunters to submit the bear’s baculum to prove the sex of the animal.

“I think the biggest [polar bear baculum sample] I’ve seen was 225 to 230 millimetres,” Bourgeois says. That would have come from a big animal.

It’s a far cry, though, from the walrus baculum she was swinging around earlier.