Creature Feature – Polar Bear

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International Polar Bear Day is coming up on February 27th! Read on to learn more about these cold loving sea bears and how you can help them!

Ursus maritimus
Range: Canada (home to 60% of the population), Alaska, Greenland, Russia, & Norway
Height: 3.5-5 feet at the shoulder. Can be over 10 feet tall when standing on hind feet.
Weight: Females 330-650 pounds. Males 775-1200 pounds.
Lifespan: 15-18 years in the wild. Mid to late 30s in captivity.

The polar bear is the only bear classified as a marine mammal. Polar bears live in the circumpolar north areas where they primarily hunt seals at openings in the sea ice called leads. There are 19 distinct populations of polar bears, but no subspecies. Polar bears do not live in Antarctica. Penguins do.

Polar bears are at the top of the food chain in the Arctic and play an important role to the ecosystem by preventing an overpopulation of seals. They feed on ringed and bearded seals, the highest calorie food source available. All other foods, with the exception of beached whales, don’t provide enough calories to sustain the bear’s body size or to build up the fat reserves they need to sustain themselves in between meals.

Polar bears are built for living in the arctic climate where in winter temperatures can drop to -50 degrees Fahrenheit and stay that way for days. In fact they have more problems with overheating than they do with the cold weather. That’s why they walk at a leisurely pace. They quickly overheat when they run.

Their fur consists of a dense undercoat topped by longer guard hairs. These two layers of fur provide excellent insulation. And their fur isn’t actually white! The hair shafts are pigment free and transparent with a hollow core. It only appears white because it reflects all visible light. Polar bears look whitest when they are clean and in the sunlight. Oils from the seals they eat can make them look yellow, and sometimes captive polar bears can appear green from the algae that grows on the fur when they are living in warm and humid environments.

In addition to their insulating fur coat polar bears have compact ears and a small tail to prevent heat loss, and a layer of fat underneath their black skin that can measure 4.5 inches thick. When in water they especially rely on this thick layer of fat to keep themselves warm as wet fur makes for poor insulation.

Polar bear feet measure up to 12 inches across and help distribute weight when walking on thin ice. When the ice is very thin polar bears extend their legs far apart and lower their bodies to distribute their weight even more. The bottoms of their feet are covered by small bumps called papillae that grip the ice and keep the bears from slipping.

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Polar bears have evolved for a life on the sea ice, which they rely on for reaching their seal prey. But due to climate change the ice is rapidly diminishing, affecting the entire arctic ecosystem. Studies predict our planet will warm to the point where enough sea ice melts annually to lead to the disappearance of two-thirds of the polar bear population by 2050. The current decline in sea ice is already forcing polar bears to swim such long distances that they are drowning from exhaustion.

The laws of physics dictate that the world will grow warmer and warmer as greenhouse gas concentrations rise. But we still have time to save polar bears if we act soon to greatly reduce greenhouse gas emissions. Taking action now won’t result in an immediate stop to climate change, but new studies show that we’ll see the effects in about a decade.

One simple way to help reduce carbon emissions is by adjusting your thermostat a few degrees up or down, depending on the season. It may not seem like much, but home heating and cooling accounts for 17% of all global warming emissions in the United States. If every American adjusted their thermostat just one degree it would save as much energy as the entire state of Iowa uses in one year!

For more ways you can help visit PolarBearsInternational.org

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