New evidence suggests that the polar bear, Ursus maritimus, or the sea bear, started to evolve about five million years ago from brown bear ancestors. Unlike their land-based cousins, polar bears are superbly adapted for survival in the Far North on a sea ice habitat.
Polar bears live in the Arctic in areas where they hunt seals at openings in sea ice called leads. Five nations have polar bear populations: the United States (Alaska), Canada, Russia, Greenland, and Norway.
Polar bears top the food chain in the Arctic, where they prey primarily on ringed seals. They reach these seals from a platform of sea ice.
Adult male polar bears weigh from 775 to 1,200 pounds. A few weigh more than 1,200 pounds, but these individuals would be exceptional. Females normally weigh 330 to 650 pounds. It’s not uncommon for female polar bears preparing to enter maternity dens in the fall to weigh over 600 pounds.
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 2-1/2 years, learning how to hunt and survive in the harsh arctic environment.
Myths and Misconceptions
Covering its nose. Dr. Ian Stirling and several assistants used telescopes to watch undisturbed polar bears hunting seals in the Canadian High Arctic—24 hours a day when conditions permitted, in both spring and summer conditions, for several weeks each year for several years. They documented the details of many hundreds of hunts. No bear was ever seen putting a paw over its nose while stalking a seal. Nor, to our knowledge, have other polar bear biologists ever observed this behavior. Simply from a mechanical point of view, Stirling expresses puzzlement about just how a bear might walk, crawl, or stalk on three legs while holding its paw over its nose for an extended period since most stalks on the sea ice cover 50 to as much as 200 meters.
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.
Orca whale predation. Scientist Ian Stirling concedes that an orca might have an opportunity to attack a bear stranded on a remnant of ice, but it’s extremely unlikely. Neither Stirling nor polar bear biologist Scott Schliebe have ever heard of this being observed.
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.
photos through polar bears international
source: their site