Latin Name: Ursus maritimus, meaning "sea bear"
Habitat: Circumpolar regions, especially near the coastlines
where open leads afford good hunting opportunities.
Classification: Mammal, carnivore
Meet the guy at the top of the food chain. As the largest land carnivore, the polar bear has no natural predators; in most cases, hunters are responsible for premature death. The world's population of an estimated 21,000 to 28,000 polar bears live in the "circumpolar" region, where their favorite food (seals) is most plentiful and the temperatures are tolerable.
Male polar bears are "boars"; females are "sows"; their young are "cubs." Boars are at least twice as big as sows, and can weigh between 800 and 1,500 pounds.
A polar bear's paws are unusually big and out of proportion to its body. The extra-large, five-toed paws act like snowshoes, allowing the animals to walk on top of the snow instead of breaking through. They're also good for paddling when the bear is swimming. Rough pads and long hairs between the pads help keep the bears from slipping when walking or running on ice.
The polar bear's black skin is completely covered by a dense underwool and longer, hollow guard hairs. These individual guard hairs can absorb and "store" heat from the sun's rays. Water easily runs off the polar bear's fur because it is coated with a layer of natural oil. That means that after swimming, the bear's hair doesn't stay matted down to its body, which could easily mean freezing. Beneath that super-warm coat, polar bears have about 4 inches of blubber, or fat, to help keep warm. In fact, they stay so warm that if they don't move slowly, they can overheat. Sometimes they go swimming to cool off.
Think About It: What things do you do to cool off when you're too hot?
A polar bear's body shape differs from other bears in that its hind legs are longer than its forelegs, so its rump is higher, and head lower. Its body and neck are longer and flexible; even though its fur is light (white, cream, or off-white, depending on the angle of the sun), its skin, nose, and claws are black. Its eyes are dark brown. A hunting bear may covers its black nose with its paws so it can't be spotted in the snowy surroundings.
Look at the profile of a polar bear in comparison to a black or brown bear. You'll notice that its nose is slightly arched, higher at the center and dipping down at the end, whereas a brown bear's nose is concave, or "dished," and the black bear has a straight nose.
Think About It: Long hind legs offer a clue about an animal's running speed. Why would speed be important to a polar bear?
A polar bear has 42 teeth, and uses them for biting and tearing flesh when it eats. Its teeth can also tell scientists how old a bear is. Almost like a tree, each year another layer of "cementus" is added to each tooth. If you could pull a tooth and cut it in half, you could count the "rings" to find out a bear's age.
Think About It: Count your teeth. How many more teeth does a polar bear have?
How are polar bears like humans? Their body temperature is 98.6; their vision and sense of hearing are similar to humans, but their sense of smell is more acute. Polar bears love to eat seals, and can smell one more than 20 miles away.
How are they definitely not like humans? The female has one or two cubs, each weighing about a pound, in November or December. After a female bear delivers her babies, they stay in the den and she doesn't eat or drink anything, or produce any solid waste, for about five months! The mother and young do not come out of the den until March or April, and the "kids" don't leave mom's side until they're well past 2 years old and practically as big as she is.
Think About It: Test your sense of smell. Experiment with different foods to see how far away you have to be before you can't smell them.
In Alaska, as in other circumpolar homelands, the Native peoples hunt the polar bear for its hide and meat. The fierce bear is an expert hunter, and people are among its prey, so a Native hunter truly enters dangerous ground when he goes out on the ice.
The bear has been a source of inspiration for Native artists as well as the skin-sewers who made warm and useful clothing. Images of polar bears appear in ivory carvings, scrimshaw, parka trim, sewing kits, and more.
Think About It: Why is camouflage as important to a Native hunter as it is to the polar bear?
For more information, check out the Sea World web site at: http://www.seaworld.org/infobooks/PolarBears/home.html
Polar Bear International
http://www.polarbearsinternational.org/
Watch the polar bears of the San Diego Zoo on their live Polar Cam:
http://www.sandiegozoo.org/zoo/expolarbearplunge.html
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Polar Bear
Anchorage Daily News.
Anchorage Daily News.
Image provided by BP Exploration (Alaska) Inc.
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