WHERE DO POLAR BEARS LIVE?
Polar bears live in one of the most hostile environments on our planet – the Arctic. Temperatures here can get as low as -50 degrees Celsius. Polar bears have a thick layer of blubber and very thick insulating fur which helps them to stay warm. They’ve also evolved to have very small ears, a short tail and short legs. This keeps their surface area to volume ratio low, which helps them conserve heat.
WHAT DO POLAR BEARS EAT?
Polar bears require a diet high in fat in order to maintain their body temperature in the freezing Arctic conditions. Seals provide the perfect source of food for them – rich in fat and calories! To catch a seal requires a game of stealth. Seals are exceedingly fast swimmers, and although polar bears are also very competent in the water, they would be nowhere near fast enough to catch a seal. Instead, a polar bear will lay in wait on the ice, staying motionless next to a breathing hole waiting for an unsuspecting seal to come up for air!
DO POLAR BEARS DRINK WATER?
Living in a frozen landscape presents many challenges for a polar bear – one of which is how to stay hydrated! What do you drink when your water sources are either frozen or are salty sea water?
The answer lies in their food source – seal blubber! Polar bears will often choose to eat the fat (blubber) of a seal over the muscle meat. As well as being higher in calories, the blubber will actually release water when broken down in the body, unlike muscle meat which uses up water in the body to break it down. So, the more blubber a polar bear can eat, the more hydrated they will be.
WHERE ARE POLAR BEAR CUBS BORN?
When a female becomes pregnant, she builds a snow den in which to give birth and rear her cubs for the first few months. The cubs are so tiny when born, that without the protection of this den they would freeze. At the age of around 3 -4 months, mother and cubs will emerge from their den and make their way towards the sea ice.
The cubs will then stay with their mum for the next two years of their lives, roaming the sea ice and surrounding waters, learning how to catch food, and navigate their hostile environment before they’re ready to go it alone.
WHY ARE POLAR BEARS WHITE?
It may look like polar bears have white fur, but in fact each strand is transparent and hollow, reflecting its surroundings and giving the impression of being white. This is great for camouflage, enabling polar bears to have the element of surprise when hunting prey.
Polar bears’ reflective fur camouflages them against their surroundings.
HOW DO POLAR BEARS STAY WARM?
Living in the arctic comes with one very obvious challenge – how to stay warm! Whilst most bear species such as grizzlies and black bears hibernate in warm dens in the winter, polar bears (with the exception of pregnant females) will spend the arctic winter outside.
Consequently, polar bears have evolved to be incredibly good insulators and heat generators. In fact, they lose such little body heat to their surroundings that they barely show up on thermal imaging cameras! This is thanks to their 20cm thick layer of blubber, and their dense, waterproof fur.
Their expert heat generation capabilities are thanks to their evolved DNA. A recent scientific study at the University of Buffalo has found that polar bears have evolved genetically so that they can use more of their body’s nutrients for generating heat than for creating metabolic energy. This relies on them having a diet rich in calories, and so an abundance of food such as seals is really important to a polar bears survival.
ARE POLAR BEARS ENDANGERED?
Polar bears are classified as vulnerable on the IUCN red list. Studies on polar bear populations found a 40% decline between 2001 to 2010. There are currently estimated around 26,000 polar bears left worldwide, but scientists are very worried that with the effects of climate change, we could lose most these in the next 80 years.
Global warming has caused a huge reduction in the amount of sea ice in the Arctic, which poses huge problems for polar bears. Without the ice, it’s very difficult for them to find food, and resting places. Hungry bears will lose weight rapidly, and their subsequent health decline in turn makes it much harder for them to breed. The leading cause of cub mortality is a lack of food, for either the cubs, or the mothers.
Other threats to polar bears include an increase in commercial activity such as oil and gas explorations, more conflicts with humans, pollution, and unsustainable hunting.
HOW CAN WE HELP POLAR BEARS?
Anything that helps tackle climate change and water pollution is good news for polar bears. Whether it’s cycling instead of taking the car, switching to green energy, avoiding single use plastics, or putting pressure on your politicians to do more. The more we can do to stop global warming and clean up our oceans will ensure that polar bears still have a future.
You can also read more about conservation group Polar Bears International and their conservation efforts in A Polar Bear Adventure.