Honour thy polar bear

Opinion

Hey there, time traveller!
This article was published 27/02/2021 (1676 days ago), so information in it may no longer be current.

Today is a great day for Manitoba’s most famous, fearsome and furry residents.

That’s because Feb. 27 is officially International Polar Bear Day, a day set aside to raise awareness of the issues facing these iconic creatures and the ways in which we humans can reduce our carbon footprint.

For the record, this unofficial holiday was created by Polar Bears International, an advocacy group run by conservationists, scientists and volunteers working to educate the public about the effects of climate change on the Arctic region.

More specifically, they focus on how global warming is slowly destroying the habitat of polar bears and adversely affecting their population. Today is a special day for Manitobans, because this province is home to the northern community of Churchill, long considered the Polar Bear Capital of the World.”

“We founded the day to coincide with the time period when polar bear moms and cubs are snug in their dens. As part of our celebration, we focus on the need to protect denning families across the Arctic,” PBI’s website says.

“This year, we’re launching a campaign to fund the development of a new tool to find and map den locations to make sure moms and cubs aren’t disturbed. By protecting dens, you’ll protect cubs, helping to ensure their future.”

To help you celebrate these mysterious and massive Manitobans, today’s frigid list explores Five Fascinating Facts You Probably Didn’t Know About Polar Bears:

5) The bear facts: They poop glitter

Bear with us: All that glitters is definitely not gold — because at Winnipeg’s Assiniboine Park Zoo there’s a chance it just might be polar bear poop. That’s because for several years the polar bears living at the zoo had a special ingredient added to their diet — non-toxic glitter. “The Assiniboine Park Zoo’s Conservation and Research team works with other North American zoos to study polar bear hormones found in fecal samples,” the zoo posted on its Facebook page in November 2019.

“To keep track of whose poop is whose, each polar bear is assigned a colour of non-toxic glitter. The glitter is mixed into their food and comes out the other end undigested 24 hours later! Our animal care staff collect the sparkly poop which gets saved in a freezer before being analyzed in a laboratory. This spring, our team sorted and shipped over 1,000 samples of polar bear poop to the Cincinnati Zoo and Botanical Garden to look at how hormones develop.

This research helps us understand polar bear reproductive biology, which can help us better understand the polar bears in our care and help us protect polar bears in the wild. Sometimes, science can be sparkly AND stinky.” The glittery samples allow zookeepers to track what is going on inside the bear’s bodies. They are also used to track stress hormone levels and see how the bears are adjusting to life inside the zoo and in captivity.

“By looking at hormone profiles over time in captive bears we can go and look at scat that we collect along the coast of the Hudson Bay and we can learn a lot from that,” Dr. Stephen Petersen, head of conservation and research at the International Polar Bear Conservation Centre, said in 2016. “What we can do in the zoo to help manage populations and maintain populations in the wild… where we really want polar bears to be forever.”

4) The bear facts: Like cars, they come in hybrid editions

Bear with us: Due to changing climates, scientists have observed polar bears moving further south, and meeting up with grizzly bears, who have been expanding their habitat north. The two huge bears are closely enough related that they’ve been successfully breeding and creating what appears to be a whole new hybrid bear species. “As recently as 2006, genetic testing confirmed the existence of polar bear-grizzly bear hybrids, also known as ‘grolar bears’ or ‘pizzly bears,’” according to the website of the World Wildlife Fund.

“The hybrid physically resembles an intermediate between the two species, but as wild hybrids are usually birthed from polar bear mothers they are raised and behave like polar bears. The ability for polar bears and grizzly bears to interbreed is unsurprising when you consider that polar bears evolved from brown bears as recently as 150,000 years ago!” In May 2016, an odd-looking bear shot by a hunter in Nunavut turned out to be the hybrid. Didji Ishalook, 25, spotted the animal on top of a hill near his home community of Arviat, about 260 kilometres north of Churchill. From a distance he thought it was either an Arctic fox or a small polar bear. Up close it was shaped more like a grizzly, but its colour was like a polar bear. “It turned out to be a grizzly half-breed,” Ishalook told the CBC.

“It looks like a polar bear but… it’s got brown paws and big claws like a grizzly. And the shape of a grizzly head.” Dave Garshelis, a research scientist from the Minnesota Department of Natural Resources and one of the world’s foremost bear experts, agreed with Ishalook. “With climate change, grizzly bears are moving further north, so there is more overlap between grizzly bears and polar bears in terms of their range,” Garshelis said at the time.

“There are even American black bears that are moving further north. And a few black bears have been spotted outside of Arviat.” He noted a hybrid bear is unofficially called a grolar bear if the sire is a grizzly bear and a pizzly bear if the sire is a polar bear. A third potential name is nanurlak — a word combining the Inuit-language words for polar bear and grizzly, nanuk and aklak.

3) The bear facts: They are marine mammals

Bear with us: You will likely not be surprised to hear this, but on land, there is literally no larger carnivore than a polar bear. “Male polar bears can grow up to 2.8 metres long and 800 kilograms in weight. Although this is the larger end of the spectrum, on average, polar bears are still considered to be the biggest bear, rivalled only by Kodiaks, a subspecies of the brown bear that is native to Alaska,” according to oceana.ca.

A single male polar bear can weigh as much as 10 men, provided they are not as husky as this columnist. What you might not know, however, is that polar bears are the only bear species to be classified as a marine mammal. “Although polar bears spend a lot of time on land, they are perfectly suited for life in the ocean. Their snout, head and body are longer and more streamlined than other bears, allowing them to swim more efficiently. Their large wide paws act as paddles to propel them through the water and their hind paws act as rudders helping them steer,” notes oceana.ca. While most are born on land, they depend on the ocean for survival and their scientific name (Ursus maritimus) means “maritime bear” or “sea bear.”

These kings of the Arctic are not land-bound like other bears. “Polar bears are the only species of bear that depends on the ocean ecosystem to survive. Their life is tied to the sea ice and to the abundant world that blooms, swims and paddles beneath their paws,” the website of Polar Bears International notes. It’s not that they prefer living on sea ice; it’s that they literally need the ice to survive. “A polar bear’s hunting and eating patterns depend completely on sea ice. Why? Because seals depend on it — and seals are the only food source with a high enough fat content and enough calories to keep a polar bear healthy. Polar bears can only reach seals from the platform of sea ice. While they are good swimmers, catching a seal in open water is extremely challenging and unlikely.”

2) The bear facts: Their time is running out

Bear with us: The climate-change clock is ticking on the world’s polar bear populations and it won’t be all that long before time runs out. That’s the grim view of a group of Canadian and U.S. scientists who last summer announced they have calculated when these iconic creatures will reach the end of their time on the planet.

According to the Canadian Press, the researchers used data on shrinking sea ice and detailed information on what the bears need to stay healthy and rear cubs to project the survival odds for 13 of the world’s 19 bear populations through to the end of the century. “It’s very grim work,” said Peter Molnar, a University of Toronto biologist who is the lead author on the study, published last year in the journal Nature Climate Change. “The sad part is that we have known for a very long time what is going to happen.” The researchers weighed what the bears need to live, reproduce and rear cubs against what their environment offers them. Polar bears depend on rich, fatty seals to get them through long periods of fasting, and they can only hunt that prey from sea ice — a platform proven to be rapidly shrinking due to climate change.

The U.S. Fish and Wildlife Service listed the polar bear as a threatened species throughout its range in 2008 due to the threat of extinction posed by the loss of sea-ice as a result of climate change. Foods on land, such as bird eggs, just don’t have enough calories to keep the bears going. “There’s simply not enough energy on land in the places where bears live,” Molnar told CP. Even if the world were to manage to reduce greenhouse gas emissions, bears in northern Ontario on the south coast of Hudson Bay will likely have trouble raising new bears by the end of this decade. Their cousins along the west coast of Hudson Bay would likely follow a year later and those in the southern Beaufort Sea a few years after that. By the early 2040s, bears in Davis Strait would join them.

As things stand, reproductive failure would become inevitable for Hudson Bay and Davis Strait bears beginning in the 2060s. By the 2080s, it’s likely that adult bears in those regions would be starving to death. “My hope is that showing how grim and dire the situation really is will emphasize one more time how urgent the problem of dealing with climate change is,” Molnar said. “We know what needs to be done.”

1) The bear facts: They aren’t white

Bear with us: If there is one scientific fact that everyone thinks they know about polar bears, it is this — these majestic creatures are as white as snow. As hard as it may seem to believe, the truth is this — polar bear fur is translucent, and only appears white because it reflects visible light. Beneath all that thick fur, their skin is jet black. It is, of course, vitally important that these apex predators are coated in fur that appears white, because it provides the perfect camouflage as they sneak up on tasty seals.

Imagine how much luck a brown bear — a close relative of the polar bear — would have trying to blend in with bright white snow while hunting. “Polar bear fur is actually see-through, but it takes on a white colour because of its structure,” The Washington Post reported in a 2017 feature. “Your hair gets its colour from something called pigment. Different types of pigment form in different amounts to create various colours when light hits them, sort of like when you mix shades of paint.

But polar bear fur has a structural colour, which comes from the way light bounces around the structure of the hair itself — no pigments required. Unlike human hair, polar bear fur is hollow like a straw. These tubes are too small to see without a microscope, but there’s enough room for light to scatter inside. When the bears stand in the sun and all that light bounces off them, they look white.”

It had been thought the structure of the hairs allowed the bears to absorb more warmth from sunlight, but apparently that is not the case. As for odd-coloured bears, The Post notes: “If you occasionally see a polar bear who looks a little green, hollow hairs are to blame. Tiny plants called algae sometimes grow inside their hollow hairs. The space where light would usually scatter to create white colouring is filled with green stuff instead, so the bears look like they just took a tumble in some fresh-cut grass. This happens only when it’s quite balmy.” And as Kermit will tell you, it ain’t easy being green.

doug.speirs@freepress.mb.ca