It is always endearing to watch a polar bear play in the snow, or a penguin waddle across the ice. As humans, however, we often wonder why they do not suffer from the exposure like we would. It is logical to say that they are made to withstand the cold temps, but how do their bodies works? There are some key protective components that these animals have to help them get through the day outside. They even seem to enjoy life in the snow, in most cases.
Animals that live in the coldest places on earth are warm blooded. They do not have to bask in the sun, like lizards, to raise their body temperatures. Cold blooded animals would simply die off and would likely never warm up enough to be active. Bears, penguins, and seals are all warm blooded animals. They must keep their internal temperature up to 95 to 107 degrees Fahrenheit to survive. They are susceptible to hypothermia, just like humans. Even with this limitation, seals manage to go for a swim in water that is often near the freezing point.
There is some restriction on the size of an ectotherm that can survive in the wild in Antarctica. These are things like insects. They must remain at 13mm or smaller to be able to remain heated. The energy gained from the environment in the arctic would not sustain an ectotherm and larger than this. They need enough energy to keep going once they are cooled. The cooling temperatures are also much lower in the arctic.
There is nothing keeping the surface of penguins any warmer than the incredibly cold water they swim in. Yet they seem able to swim for hours with no issues. Water cools the body much faster than air, making this seem like a dangerous situation. Animals in Antarctica, however, have a layer of blubber beneath the skin that keeps that cold on the surface of their bodies. Their core temperature remains stable at all times. Flippers and flukes are meant to release heat when an animal need to cool down. The blood vessels in these appendages can carry cold blood back to the inside of the body to be warmed up if the body is cooling too much.
These cold weather animals are perfectly suited to maintain a safe temperature in their natural habitats. They are met with many sustainable food sources that other animals are not able to reach, due to intolerance of the cold. Their physical abilities have made them able to live somewhere that can also sustain them with proper nutrition.