Adult male polar bears can weigh up to 460 kilograms but females are much smaller, weighing up to 250 kilograms. A large male can also measure over three metres in length and stand over 1.2 metres in height from ground to shoulder. On average wild polar bears have a lifespan of 20 to 30 years.
The Arctic ice bowl is one of the most harsh and unforgiving environments on earth, and one to which the polar bear is superbly adapted. Winter temperatures can drop to minus 30 degrees centigrade but the bears’ two layers of fur and underlying blubber help prevent heat loss.
Polar bears have the same body temperature as humans. They have black skin and transparent, hollow hair which acts like optical fibres, channeling sun light to the black skin where it is absorbed as heat - a fantastic adaptation to a cold environment.
Fur between the bears’ bumpy black footpads and curling claws enable an excellent grip on ice.
Polar bears are fastidious about keeping their coats clean. Having feasted for 20 minutes they then spend just as long again cleaning themselves up.
A large male can measure just over three metres in length and stand over 1.2 metres in height from ground to shoulder. If stood on its hind legs it can be as tall as an elephant. Their enormous paws measure up to 32 centimetres across.
They spend most of the time hunting seals, who lie below the surface in their air-holes. Polar bears can detect the smell of a seal’s lair from up to two kilometres away. They then stomp through the snow and ice and grab the seal before it can escape into the water.
However, polar bears can also close their nostrils and hold their breath for two minutes under water, enabling them to sneak up and grab seals laying out on the edges of ice floes.
Seals are the mainstay of the polar bear diet and are essential to its survival, but when the going gets tough polar bears will eat seaweed, birds’ eggs, lichen, berries and young walrus. A male polar bear, hungry from the lean pickings of winter, will even eat its own cubs as they emerge from their snowy dens for the first time.
Polar bear cubs are born in midwinter and emerge from the den in March or April to begin survival lessons through play and imitation of the mother. The usual litter numbers two and more is rare. Weighing little more than half a kilogram and at about 30 centimetres long, cubs survive solely from the warmth of their mother's fur and her rich fatty milk.
The polar bear is at the top of the food chain in its environment. Occasionally, while defending its young, a large bull walrus can wound or kill a polar bear with its tusks. Polar bears rarely kill one another but the males can fight savagely during the brief mating season. The biggest threats are the human hunter, pollution and climate change, although the polar bear is not officially an endangered species.
Jim McNeill, Founder and Leader of the Ice Warrior Project had a close encounter with a wild polar bear.
One spring day I decided to visit the ancient Thule ruins where the original settlement was situated. In the corner of my eye I was aware of movement and turned to face a big male polar bear rummaging through the waste of the township. There was more movement and I soon realised I was watching a whole load of savaging polar bears – I counted 13 in all! This was very unusual behaviour; bears are normally such solitary creatures!
In Ontario, Canada, The Polar Bear Conservation & Educational Habitat has a wading pool where visitors can swim with the bears albeit separated by a wall of toughened glass.
- Inuits call polar bears "Nanuk" and although hunted they are greatly respected.
- Polar bears can close their nostrils and hold their breath for two minutes under water.
- They sleep about seven hours a day at a stretch plus naps.
- Polar bears are fastidious about keeping their coats clean. Bears might feast for 20 minutes then spend as long again cleaning themselves up.
- They have the same body temperature as humans.
- They have black skin and tongues.
- Polar bears are born blind, toothless and with just a thin covering of hair.
- Attacks by polar bears on humans are rare and only occur when the bear is provoked or undernourished.