Polar Bears: Meet the King of the Arctic
The polar bear may seem cute and cuddly, but these mammoth mammals of the Arctic are a hardened species, set out to survive in these subzero temperatures, plunging to as much as -45o Celsius. The polar bear, Ursus maritimus, which means sea bear, have been recorded to weigh as much a 1,000 kilograms, and can grow to as big as ten feet tall, when standing on their hind legs. That’s a massive body mass, which includes a thick layer of blubber nearly 4.5 inches thick. Wrap this up with two additional layers of fur, which covers all of the bear’s anatomy except their nose and footpads, and Ursus maritimus stays as snug as a bug. Pure white to creamy yellow/light brown in colouration, depending upon season and angle of light, makes for a perfect combination for surprising prey.
Other essential parts of the anatomy, such as the paws and snout, help them thrive in these harsh conditions. Polar bears’ paws are large compared to their body size. Measuring 12 inches, they include thick, curved, non-retractable claws, essential for catching large prey, as well as for traction when running on ice.
Small bumps, known as papillae, are also present and these help them keep their grip when manoeuvring slippery ice. Up to half the length of the bear’s toes is covered with a swimming membrane, which enables them to swim at a rate of six miles per hour, and they’re known to be competent swimmers as far as 320km from shore.
The bear’s sense of smell is extremely acute, and becomes the most important sensory for detecting land prey. Able to smell a seal from over one extremely important to this species’ survival, as snowy weather conditions impair its eyesight, which is no better than that of a normal human being. These factors firmly put Ursus maritimus at the top of the Arctic food chain.
Unfortunately, despite their great prowess, the polar bear population is dropping quickly, mainly due to the damaging effects of global warming. As the Earth heats up, larger quantities of ice are melting earlier in the year, removing the vital hunting platforms which polar bears use to hunt seals. This habitat loss is preventing polar bears from building up the requisite fat reserves to survive in the harsher and leaner parts of the year, with many succumbing to malnutrition. In addition, the loss of ice is forcing the bears to swim further and further between landmasses, draining energy that is vital for healthy reproduction, body conditioning and general survival.
This article was originally published in How It Works issue 04
For more science and technology articles, pick up the latest copy of How It Works from all good retailers or from our website now. If you have a tablet or smartphone, you can also download the digital version onto your iOS or Android device. To make sure you never miss an issue of How It Works magazine, subscribe today!