Happy International Polar Bear Day! On this February 27, we focus on the polar bear, king of the Arctic. Everyone knows what a polar bear looks like, but there are quite a few facts that are not well known. Did you know what color their skin is? More fun facts below.

Polar bears are white; but the skin under its fur coat is black! This helps it absorb heat and keep warm in the Arctic.

Polar bears don't have white fur at all – their fur is actually translucent. It looks white only because of the way it reflects light.

It is the biggest bear among the eight members of the bear family. Also, polar bears are the largest extant land carnivore. The largest individual on record weighed more than 1,000 kilograms.

A polar bear that measures 2.4-3 meters has a super mini tail of 7-13 centimeters. Isn't that cute?

Many zoos have polar bears on display; but their natural habitats exist only in five nations: Denmark, Norway, Russia, the United States and Canada. It is a vulnerable species on the IUCN red list, with an estimated population of no more than 31,000.

All mammals need to drink fresh water, and polar bears are no exception. Living on ice surrounded by the ocean, how can they stay hydrated? Polar bears do not need to find water – instead, they hunt seals, and are able to produce water through the metabolism of fats found in seal blubber.

...which can detect seals nearly 1.6 kilometers away and buried under one meter of snow. Its hearing and long-distance vision are excellent, too.

Most terrestrial animals in the Arctic can outrun polar bears on land, as polar bear can overheat quickly. And most marine animals the polar bear encounters can outswim it, too. So polar bears rarely hunt seals in open water. The main advantage it has is its stamina: polar bears can swim for hours, even days. 

Scientists have warned that the current warming trend imperils the survival of polar bear. As sea ice melts early, polar bears are driven to shore before they have built sufficient fat reserves to survive the period of scarce food in the late summer and early fall. Reduction in sea-ice cover also forces bears to swim longer distances, which further depletes their energy stores and occasionally leads to drowning. 

U.S. Geological Survey scientists have predicted two-thirds of the world's polar bears may disappear by 2050, due to the shrinking of summer sea ice caused by climate change. To avoid the loss of this species, we need to do everything we can to stop global warming.

(All pictures via VCG)

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