Polar Bears: A Life on IceBy Hannah Schardt
For most animals, living in the frigid Arctic would be too much to “bear.” But for polar bears, all that ice is very nice!
These two roly-poly polar bear cubs follow their mom from one chunk of ice to another, nearly splashing into the slushy seawater. Wouldn’t a leap like this make you freeze with fear? Not so for these little cubs. Just like their mom, they’re built for a life surrounded by chilly water, snow—and especially ice.
ON THE HUNT
Polar bears are the largest bears in the world. A male may weigh as much as seven grown men! So it’s no surprise that these bears need a whole lot of food to keep their big bodies going. And they get most of that food by hunting their favorite prey: ringed seals.
The seals they eat hang out mostly in icy Arctic waters. But like all marine mammals, the seals must come up for air. So polar bears prowl the edges of the ice that forms on the Arctic sea each fall. When a seal pops up to breathe, a waiting bear may grab it and drag it onto the ice for a meal.
All polar bears need to eat a lot. But a mom-to-be really needs to chow down and fatten up before winter. Winter is when she settles into her snowy den to give birth—usually to two cubs. She won’t eat again for four months or longer! And she uses up a lot of stored fat to make milk for her cubs.
Once the babies are old enough, they follow Mom out into the big, icy world. It’s spring, which means the sea ice will soon be melting. And once the ice melts, seals become much harder to catch. So while the sea is still frozen, Mom must snag as many seals as she can for herself and her babies. Her hungry cubs trail along, learning how to hunt.
Polar bears spend most of their time on land or ice. But they are also super swimmers. Their big feet move them quickly through the water—faster than an Olympic champion swimmer! And they’re not just sprinters. Polar bears have been spotted swimming more than 50 miles from land.
Of course, a person could never spend so much time in such cold water. But a polar bear has a special layer of fat as thick as your leg. It keeps the bear warm even underwater—sort of like a built-in wetsuit!
FUR & SKIN
Two layers of thick fur keep polar bears warm. The fur may look white, but each hair is actually see-through. The skin beneath is black, which absorbs warmth from the sun.
This sensitive sniffer can smell a seal on the ice from more than a mile away. The nostrils close tightly underwater. That keeps a swimming bear from getting a noseful of icy water!
Sharp teeth are great for catching food and tearing off hunks of fat and flesh. But these teeth don’t need to chew; most hunks are swallowed whole.
These dinner plate-sized paws are slightly webbed to help with swimming. Bumpy footpads help them grip slippery ice.
TROUBLE IN “PARAD-ICE“
The Arctic sea where polar bears live should freeze over in early autumn—and not melt until late spring. But human-made gases are making the Earth warmer. This causes the sea ice to freeze later in the fall and melt much earlier in spring. Without their sea-ice hunting ground, the bears go hungry.
Scientists have recently seen polar bears hunting seabirds and even dolphins—not prey they normally eat. That may sound as if the polar bears are learning how to survive in a warming world. But scientists say the bears can’t get enough fatty meat from those animals to survive. Many people are trying to figure out ways to stop the planet from heating up even more. That would be good news for Earth—and great news for the polar bear.