Ursus maritimus… that’s the Latin name of the majestic polar bear, the world’s largest terrestrial carnivore who inhabits the far northern regions of Greenland, Norway, Siberia and Canada.
Its name means “sea bear,” which is quite appropriate since polar bears spend most of their lives in, on or around water — mainly on the sea ice of the Arctic Circle.
Polar bears are among the largest land mammals on Earth. Male bears can weigh 700 to 1,400 pounds and stand 8 to 10 feet tall.
While polar bears are excellent swimmers, they prefer to stay on top of the ice that covers the Arctic Sea most of the year.
Why do they spend so much time on the frigid Arctic ice? The Arctic waters and ice floes are where their favorite food — seals — can be found.
Polar bears will also occasionally eat other animals, including walruses and dead whales, but seals are by far their favorite food. Seals can be tricky to catch, though, so polar bears must hunt with great stealth and patience. Fortunately, their white coloring helps them blend in with their icy surroundings.
So how did polar bears that live in a snowy-white world come to have white fur? Believe it or not, their hair isn’t actually white!
Their long outer hairs, which protect their soft, thick undercoat, are hollow and transparent. The thinner hairs of their undercoat are also colorless.
Polar bear hair looks white because the air spaces in the hairs scatter light of all colors. When something reflects all of the visible wavelengths of light, we see the color white.
Some scientists believe the polar bear was once a close relative to the brown bear. They think that, over time, polar bears moved to the Arctic, where they adapted to their surroundings by developing fur that would help them blend in with the harsh, white Arctic ice.
Not all polar bears look white, though. If you’ve ever seen a polar bear in a zoo, you may have noticed that its fur can appear almost green.
Scientists discovered that algae from the pond waters in the bears’ enclosures made the bears turn green. They learned these algae were found not on the surface of the hairs but inside the hollow hairs!