The big white bear of the Arctic is the joint largest member of the bear family, with the Kodiak Bear, and the world’s largest land based carnivore.
Polar Bears lead a semi marine existence, spending much time on the
sea ice hunting for
seals and they are streamlined for
swimming and have been documented as swimming long distances when they need to. 60miles (100km) has been recorded.
Polar Bears are mostly solitary, they hunt alone, coming together to mate, but there are many instances recorded that when they do come together, the bears appear to be friendly to each other often
play fighting for long periods of time and laying up in
day beds in snow banks together.
A female has one to three
cubs which are born blind and nearly hairless in
dens under the snow in December, she produces a milk rich in fat for them until they emerge from the den in March. She will stay around the den for nearly two weeks while the cubs get stronger and more active and then she needs to feed because it could be 8 months since she last ate. The family unit will stay together for around two years, when their mother chases them away the cubs will sometimes stay together for a time, sharing food.
A Polar Bear’s fur is translucent rather than white and carries the light down to its black skin. The combination of fur and subcutaneous fat is so effective that when scientists tried counting bears by taking infrared, heat sensing, pictures from planes, they could only see the bears that were breathing out. The rest of the bear was invisible. In 2003 a bioengineering student discovered that Polar Bear fur has the same radiative properties as snow, and had the Polar Bear Biologist been using UV film they would have seen every bear.
The Polar Bear is genetically very close to the
Brown bear and there had been speculation for a while that with Climate Change allowing Brown bears to forage further north, there was the chance of a hybrid occurring. In 2006 DNA testing confirmed that this had happened, a coffee coloured Polar bear was shot by a sports hunter at Sachs Harbour on Banks Island. Culturally the bear was a Polar bear, and so we can assume that his mother probably was also. It is believed that there have always been the occasional cross between the two, including perhaps the huge MacFarlane’s Bear, acquired by MacFarlane from the Inuit in 1864. But in the absence of DNA testing at the time, no one could be sure.
Polar Bears and Man
The
Inuit,
Yupik and
Chukchi have shared the Arctic with Polar Bears for thousands of years. Polar Bear remains have been found at hunting sites that date back 2,500 to 3,000 years. Polar Bears supply skin for clothing and boots, meat for both men and dogs to eat and the claws were used as talismans. Care was always taken to dispose of the liver, preferably back into the sea as it is very high in vitimin A and is poisonous to man and dogs. The polar bear features in the folklore of the peoples of the coastal arctic. Indigenous hunting of Polar Bears is closely controlled throughout the Arctic and totally banned in Russia although it is believed that a substantial amount of poaching of Polar Bears is done there.
To feed in the winter, Polar Bears use the 'Ring of Life' an area of tide cracks and polynyas that stretches around the Arctic Ocean, seals need to breathe air and the ring of life is where they can do this easiest. Any siting of
Oil or gas development in this region or close to the denning areas could have dire consequences for the Polar Bears.
Being at the top of the Arctic Food Chain, Polar Bears are the Arctic's most contaminated mammal. They already accumulate the toxins, mostly PCB's, from the animals they have eaten into their own body fat, but although levels of these continued to rise after the substances were banned, it now seems that levels in Polar Bears are starting to fall again.
Status
In 2008 the United States department of the interior listed the Polar Bear as a threatened species under the Endangered Species Act. Biologists estimate that there is a world population of 20-25,000 polar Bears.
The main threat to polar bears from
climate change is that of
starvation from habitat loss, as the sea ice area in the arctic declines, the bears have less sea ice from which to hunt seals and are more at risk from drowning as this ice thaws under them too far from land. Although the IUCN ACIA and US Geological Survey express concerns about the impact of Global Warming on Polar Bears, there isn’t a total consensus and one leading Bear Biologist has gone on record, saying that many of the Canadian populations are stable or increasing
Text © B & C Alexander
