Polar bear

Ursus maritimus

Polar bears range over one million square miles, living near coastal waters on sea ice and islands encircling the North Pole. Their range covers waters off the north and northwest coasts of Alaska, the Canadian Arctic, Greenland, Svaalbard, northern Europe and northern Russia. They travel with the seasonal movement of sea ice.

The worldwide population of 20,000 to 25,000 polar bears is expected to continue to decline due to the warming and melting of sea ice, a vital polar bear habitat. According to scientists at Polar Bear International, a research and stewardship organization, if current trends continue, two-thirds of the world's polar bears will vanish within the next 40 years and the rest are likely to disappear by 2100.

Did you know?

  • Up to four inches of blubber under the skin keeps polar bears warm in subzero temperatures. It also makes them more buoyant so they can swim long distances.
  • Polar bears have been seen swimming in Arctic seas more than 100 miles from the nearest ice or land mass.
  • Polar bears are the largest member of the bear family.
  • "Ursus" means bear; "maritimus" means relating to the sea.
  • Polar bears are considered marine mammals because they take 100 percent of their sustenance from the sea.
  • Polar bear females den up in the fall to give birth to and nurse their cubs and emerge nearly five months later in early spring. They do not eat anything during this time and frequently lose half their body weight in the process.

Polar bear behavior and facts

  • The bear's white or yellowish coat, or pelage, is an adaptation that camouflages it from its prey. It lies on sea ice, waiting for a seal to pop out of its breathing hole. As the seal looks up from below, the bear blends in with the icy landscape, making it hard to see until it is too late.
  • The large size and partial webbing of their feet help bears paddle through the sea, just as swim fins make human feet larger and more efficient at kicking. Their large paw size also helps distribute their weight so they can walk across thin ice. Even though male polar bears weigh more than 500 pounds, they can safely walk on ice that would crack under a human. The heavy fur on their feet provides warmth and traction on ice, and pads their steps so that prey animals cannot hear them.
  • Polar bears are carnivores. Their favorite food is ringed seals. They also eat bearded, harp, and hooded seals. Their keen nose allows them to smell a meal of walrus or whale carcass from miles away.
  • In summer, bears are omnivores; they need meat for its fat calories but also eat berries, crab, small rodents, seaweed, sea stars or sea cucumbers – though these have little nutrition value for them.
  • When food is plentiful, they prefer to eat only seal skin and blubber to maximize their calorie intake, leaving the rest of a carcass as a food source for other animals such as the Arctic fox.

From birth to death

  • Bears begin to breed between ages 3 to 5.
  • Breeding occurs from April to May.
  • If a bear does not put on enough fat, the embryo may not develop. This is why females frequently double their body weight before denning.
  • The gestation period is eight months.
  • In December or January, between one and three cubs are born; each about the size of a squirrel. Two cubs are common, though the number seems to correlate with the mother's body condition.
  • Polar bear cubs reach 70 to 100 pounds during their first year, nursing on milk that consists of 31 percent fat. They stay with their mother for approximately 27 months.
  • A polar bear's lifespan is 15 to 18 years in the wild; 25 to 30 years in captivity.

Vital statistics

  • Males: 500 to 1,400 pounds and 8 to 11 feet tall
  • Females: 400 to 700 pounds and 6 to 8 feet tall

Status

Because of current and likely future loss of sea-ice habitat, polar bears were listed as a threatened species across their range under the Endangered Species Act in May of 2008.

In the United States, polar bears are a federally protected species under the Marine Mammal Protection Act of 1972. Regulations prohibit hunting of polar bears by non-Natives. Eskimos and other Alaska Natives are allowed to harvest some, for subsistence and handicraft purposes.

An international conservation agreement for polar bears was signed in 1976 by the United States, Russia, Norway, Canada, and Denmark (Greenland).

Polar bears, the Oregon Zoo and you

The Oregon Zoo's polar bears are a brother and sister pair, Conrad and Tasul. They are twins born Dec. 1, 1984. Their diet includes beef fat, fish, carrots, apples, bones, a wide variety of enrichment treats and omnivore chow; a food mix similar to dog chow, produced specifically to meet the dietary needs of omnivorous animals. They live in the Polar Bear exhibit.

Polar bears are threatened due to increasing warming and melting of the sea ice they depend on. You can help save polar bears and their habitat by joining a conservation organization like Polar Bears International.

Conrad

Conrad is a male polar bear. He was born on Dec. 1, 1984 and has a twin sister, Tasul, also at the Oregon Zoo...

Tasul

Tasul is a female polar bear. She was born on Dec. 1, 1984 and has a twin brother, Conrad, also at the Oregon Zoo...