Polar Bear Fun-Facts
Evolution:
Polar bears probably first appeared 200,000 years ago during the Pleistocene and were
much larger than they are today. They descended from brown bears and are the most
recent of the eight bear species.
Scientists believe polar bears descended from a group of brown bears that became
isolated by glaciers in an area near Siberia. These bears underwent a rapid series of
evolutionary changes in order to survive—from changes in the color of their fur and
shape of their body to keener senses to sharper teeth.
Polar bears inhabit five different nations: the United States (Alaska), Canada, Russia,
Greenland, and Norway.
The polar bear is a marine mammal. Its scientific name is Ursus maritimus, meaning “sea
bear.” It is also the world’s largest land-based carnivore.
Brown and polar bears can interbreed and produce fertile young, which by some
definitions suggests they are the same species. However, they are adapted to different
habitats and behaviors and, under the climate conditions that have prevailed since the last
ice age, cannot survive very long in each other’s habitat, a factor that keeps them isolated
and continuing to evolve away from one another.
Size and Characteristics:
Polar bears are so well adapted that they are more likely to overheat than to suffer from
cold. They have two layers of insulating fur, and their small ears and tails help prevent
heat loss.
They are strong swimmers and have blubber up to 4 inches thick, for buoyancy as well as
warmth. Their large feet act as paddles and also help spread their weight for walking on
ice.
They have curved, non-retractable claws, and bumps on the pads of their feet called
papillae so they don’t slip while walking or running on ice. The claws also help hold on
to prey.
Adult males can grow to 10 feet long and 1,500 lbs. During breeding season, they fight
fiercely for a mate. Females are much smaller, reaching 8 feet and 550 lbs.
You can sometimes tell male polar bears from female by the hair on the males’ front legs.
Once mature, males tend to have much longer hair on their forelimbs.
Maternity and Family:
Females usually bear two cubs. Single cubs and triplets also occur depending on the
health and condition of the mother. Cubs stay with their moms for up to 2.5 years.
Polar bears are born blind and toothless in a den built by their mother. They spend a few
months in the den, growing rapidly from their mother’s rich milk.
A mother polar bear stays with her cubs for about 2.5 years. After they leave the den, the
protective mom leads them to the sea ice to teach them how to hunt and survive.
Adult polar bears are, for the most part, solitary animals. They have large home ranges,
or territories. When they do gather, there is a distinct social order dictated by size and age.
Movement
Polar bears walk at about three to four miles per hour. Females with small cubs slow their
speed to one and a half to 2 and a half miles per hour.
Polar bears expend more than twice the energy of most other mammals when walking or
running—probably because their bodies are so bulky.
Polar bears can run as fast as 25 miles per hour—but only for short distances. Younger,
leaner bears are the best runners. They can cover two kilometers without stopping. Older,
larger bears quickly overheat.
Polar bears have been clocked swimming as fast as 6 miles per hour. The longest
documented single swim by a polar bear was 426 miles. The trip took nine days through
waters that were 2-6 degrees Celsius!
Communicating:
Polar bears use a combination of body language and vocalizations to communicate.
 Head wagging from side to side often occurs when polar bears want to play.
Adult bears initiate play—which is actually ritualized fighting or mock battling—
by standing on their hind legs, chin lowered to their chests, and front paws
hanging by their sides
 Nose-to-nose greetings are the way that a bear asks another bear for something,
such as food. The guest bear will approach slowly, circle around a carcass, and
then meekly touch the other bear’s nose. Bears who use proper manners are often
allowed to share a kill.
 Chuffing sounds are a response to stress, often heard when a mother bear is
worried for her cubs’ safety. Mother bears scold cubs with a low growl or soft
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cuff. When a male approaches a female with cubs, she rushes toward him with her
head lowered.
Hissing and snorting and a lowered head all signify aggression.
Loud roars or growls communicate anger.
Deep growls are warnings, perhaps in defense of a food source.
Attacking polar bears charge forward with heads down and ears laid back.
Submissive polar bears always move downwind of dominant bears.
Busted myths and misconceptions:
Left pawed. Great white bears are not left-pawed. Scientists observing the animals
haven't noticed a preference. In fact, polar bears seem to use their right and left paws
equally.
Use of tools. Polar bears do not use tools, including blocks of ice, to kill their prey.
Scientist Ian Stirling believes that this idea may have come about because, after failing to
catch a seal, a frustrated and angry polar bear may kick the snow, slap the ground—or
hurl chunks of ice.
Hollow hair conducts UV light. A polar bear's hollow hairs do not conduct ultraviolet
light to its black skin. This theory was tested—and disproved—by physicist Daniel Koon.
Symbiosis with arctic fox. Polar bears do not share food with arctic fox in exchange for
the fox's warning system. Zoologists discredit the notion. Arctic fox do travel behind
polar bears and scavenge on scraps. In fact, foxes often annoy bears by nipping at their
heels in an attempt to drive a bear off its prey. Polar bears sometimes lunge at or slap a
fox. During the spring season when both polar bears and arctic fox hunt ringed seal pups,
they can be considered competitors.
Bi-polar bears? Polar bears live only in Arctic areas that surround the North Pole—not
in Antarctica, which surrounds the South Pole. School children often see illustrations of
penguins and polar bears together, but this could never happen. In fact, the word arctic
comes from the Greek word for bear, and Antarctic comes from the Greek meaning the
opposite, without bear.
SOURCE: www.polarbearsinternational.org, www.oneworldoneocean.org