Mid
October each year, 600-1000 polar bears gather along 100 miles of coast,
stretching from Nelson to Churchill, Manitoba. It is the largest concentration
of polar bears in the world. About 300-350 bears congregate in the Churchill
area, waiting for the bay to freeze over.( I hope this will continue to be
true!)
The
indigenous people, the Inuits, called 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, who has 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 guard hairs, which are
hollow and 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 reflecting 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 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,
not only can smell through 3 feet of ice, but also 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 is adequate
to sustains a bear. Summer produces slim pickings for food, and the bear pretty
much subsists on its own fat. The normal walking gait of the bear is 2 ½ miles
an hour, but it is possible for him to run 25 miles an hour.
Spring,
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. Cubs look like rats at birth weighting, only 1-2 pounds. When
born they are hairless, blind, deaf, and helpless. By the time they emerge from
the den at five months, they generally weigh 29 pounds. Moms 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.
The
size of the 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. The 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 open their eyes, and by 10 weeks, they can keep their balance. They
are 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 cub. 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 and the result can be
bloody.
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 will 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.
We saw many polar bears during our stay in Churchill
and it was a thrill every time!
No comments:
Post a Comment