Polar Bears
The indigenous people of Canada, the Inuits, call the polar bear Nanook. The Ursus Maritimus is the world’s largest terrestrial carnivore. The King of the Arctic, is a gentle, ever caring mother with an intense curiosity. Females weigh 500-700 pounds, and males from 1000-1500 pounds. Standing on its hind legs, some bears can reach a height of 10-12 feet!
Clad in insulating fur and fat, the polar bear is able to sleep through blizzards, or plunge into near freezing arctic waters. The bear’s three layer coat consists of a big layer of fat topped by skin. A thick black under coat of dense fur traps heat. The top layer of fur consists of hollow guard hairs. These hollow hairs act as a solar collector, trapping the warm rays of the direct sun, and passing them onto the heat trapping under coat.
The 4 inch outer coat appears from white to yellow, but in effect, its hollow hairs are actually transparent and reflects light. These hairs, also add buoyancy when swimming, and the matting ability and oily texture allow the animal to shed water and ice from its body.
The animals’ paws are large and rounded. The bear is capable of flipping a 500 pound seal, from the water, with one swing of its paw! Each paw has five partially webbed claws that assist in swimming. Using the front legs to propel him, and its hind legs to stabilize and steer, the bear is a strong swimmer, able to swim up to 60 miles before needing to rest. The footpads have a heavy fur coat, to protect against frostbite, but are rough enough to add traction on ice. On solid surfaces, the paws spread to distribute weight and act like a snowshoe, making them a master at negotiating over ice.
The head is long and tapered, with small ears and powerful jaws. The 42 teeth include long sharp canines, needed for piercing flesh. Their eyesight is rather poor, except under water, where they can see for 15 feet when looking for food. They tend to be far sighted, which allows them to search large areas of their environment when feeding. Their hearing, through the small fur lined ears, is nearly equal to that of humans. The ears also contain a fine network of blood vessels, which transport thermal energy to the auricles.
The polar bear has a phenomenal sense of smell, and it is said, he can smell a seal buried in a cave, under three feet of snow. The bear is often seen thrusting its nose in the air to utilize its keen sense of smell. The animal can smell food for a distance of 10 miles. On a clear day, through binoculars, its black nose can be seen from a distance of six miles!
The polar bear liver is so rich in vitamin A that it is toxic to humans. The bears are also susceptible to a parasitic worm, which is apparently contracted from eating infected seals. A grown bear’s stomach will allow him to consume 150 pounds of food at one time! However, on average, a seal every five days adequately sustains a bear. Summer produces slim food
pickings, and the bear pretty much subsists on its own fat.The normal walking gait is 2 ½ miles an hour, but a bear can run 25 miles an hour!
April–May is mating season for polar bears, with the pair remaining together for a week. Courtship and mating take place on the ice. Polar bears are induced ovulators, meaning that they do not ovulate regularly, but the mating ritual stimulates ovulation. Gestation is eight months. Mothers normally have twins, but can deliver one or up to four cubs. With the ice cap disappearing it is more common these days to see a bear delivering only one cub. Cubs look like rats at birth weighting, only 1-2 pounds. They are born hairless, blind, deaf, and helpless. When they emerge from the den at five months, they generally weigh 29 pounds. Mom can double her weight during pregnancy. Cubs are born November – February. Mom nurses her babies for five months, during which time she does not hunt or feed, but stays in the den with her babies.
A bear den is approximately 6 X 10 X 4 feet, and the temperature is 40 degrees warmer than the outside air. There are 17 known denning areas across Canada. One, 40 miles south of Churchill, is the largest. Discovered in 1969, it is a birthing den for 150 polar bears. Cubs stay with their mother 2 ½ years. Mother generally gets pregnant about every three years. Mother’s milk is 40% fat and is thick like condensed milk. At one month, the cubs crawl, at 6 weeks opens their eyes, and by 10 weeks, they can keep their balance. They mature at 4-5 years. The life span of a polar bear is usually 15-18 years, but can reach 30 years. Mothers with cubs are solitary. Polar bears are very good moms. It is not uncommon for her to run off a male, twice her size, to protect her cubs.
Polar bears are one of the seven species of bears, and is most closely related to the brown bear, with whom they can interbreed, and produce fertile offspring. An adult female polar bear is called a sow, and a male, a boar. Adult males can be aggressive and often may hurt or kill the cubs. Two males can box over females for hours often with bloody results.
A polar bear can eat 10% of its body weight in 30 minutes! The animals have well developed, strong hind leg and neck muscles. In spite of their size, they are agile in the water. Young males indulge in mock fights, called sparring, which is an impressive pastime. They spend hours wrestling on their hind legs, which will serve them well for survival and the fight for mates, territory, and food. They lick the snow to quench their thirst. The only enemy of an adult polar bear is the human.
Polar bears wander the frozen north and are constantly on the move, roaming hundreds of miles. They live on ice sheets and ice floes, which provide a base for their diet of mostly ringed seals. They’ll often wait for a seal to stick its head out of the water to breathe, then slap the seal on the head with its paw, and drag it from the water. This technique is called still hunting. The aquatic stalk is another hunting technique; the bear quietly swims through the water where a seal is sun bathing on an ice floe. The bear suddenly leaps out of the water grabbing the seal by the neck, and before the seal knows what is happening, he has become dinner. They also eat stranded whales, walruses, carcasses, human refuge, and in the summer, plants and berries.
I was very lucky to see several polar bears each day while in Churchill and I never got tired of watching them--it was a marvelous and fascinating trip well worth a repeat!
In 1960, when the bear population was estimated to be only 10,000, there was worldwide concern that the polar bear may be endangered. In 1973, in Oslo, Norway, Canada, Denmark, Norway, Russia, and the United States signed an international agreement of conservation to protect the polar bear and its habitat.
