Polar Bears: Behemoths of the North
Polar bears make the Arctic, one of the most inhospitable environments on Earth, home, and are the area’s apex predators. However, as their world begins to warm, they face an impending crisis.
The largest carnivorous mammal, although they’re born on land, they rely and live heavily on the Arctic sea Ice and are considered to be marine mammals. In fact, the bear’s scientific name, Ursus maritimus, means “maritime bear”. Their reign as the ‘Kings of the Arctic’ is in danger, however. Climate change is expected to bring about major changes to their Arctic homes, resulting in the loss of their crucial sea ice feeding grounds.
Being the largest land carnivores in the world, males can stand at over 3 m tall and weigh in at over a whopping 800 kg! Females, however, are much smaller, topping it at about 400 kg.
In order to thrive in their wintry world, polar bears have made several unique adaptations. Most notably, their fur! A polar bear’s fur serves as camouflage against the white and snowy backdrop of their habitat. Interestingly though, polar bear fur isn’t actually white,- it’s transparent. These transparent hairs reflect the colour of the bear's surroundings, namely the snow and the sky. In order to protect the bears from the cold waters they live by, they have a thick layer of fat under their skin, as well as oily water-resistant fur.
As they spend a considerable amount of time in the water, polar bears also have adaptations to help them in swimming. Their 20 cm wide paws act as paddles and their long bodies are surprisingly hydrodynamic. Polar bears can swim up to 10 days straight, covering over 600 km!
A polar bear’s diet is optimized to survive on fat. Something that a terrestrial diet can’t support. This is why they turn to aquatic prey such as fatty marine mammals. They primarily like to feed on seals.
The bears use their heightened sense of smell to track down their slippery prey. Their noses contain as much as 100x more scent receptors than our noses, and the olfactory bulb in their brain is about 5x bigger than our. This comes in especially handy when finding seal holes, holes in the ice in which seals will pop out to take a breath of air. Once they spot a seal surfacing to breathe, they’ll grab and haul it on to the ice to eat.
Although seals are their favourite, the bears will also resort to preying upon walrus, beluga whales, and birds as well as their eggs.
The Bears and Climate Change
There’s no denying it. Global warming is occurring, and this is leading to some dramatic changes in the Arctic where polar bears live. The changing climate has the potential to push these apex predators over the brink of extinction.
Polar bears rely on sea ice in order to find their prey. As temperatures get warmer, sea ice forms later in the year, forcing the bears to starve for longer. Even as the sea ice does form, there’s less of it. Less sea ice means less ground for the bears to hunt on. This is affecting the bears significantly. Currently, the IUCN Red List categorizes the bears as “vulnerable” and are threatened with extinction. In order to help these kings of the Arctic out, we’re going to need to turn the tide on climate change once and for all.