Antarctic animals are exposed to some of the coldest environments on earth. Animals survive in these harsh conditions by reducing the percentage of body heat that is lost to the environment. This can be by physical means (generally evolved over many generations) or patterns of behavior.
Thick, windproof or waterproof coats
Many Antarctic animals have either a windproof or waterproof coat. Emperor penguins are a very good example of this. These birds have four layers of scale-like feathers. These layers overlap each other, forming a good protection from the wind, even in blizzard conditions.
Thick fat (or blubber) layers
Whales, seals and some penguins have thick fat layers. These fat layers act like insulation, trapping body heat in. This is a little like wrapping yourself in a blanket, but on the inside. In some animals this is even further refined, with the animals selectively able to reduce blood flow to the blubber layers. The further the blood is from the skin surface, the less heat is lost.
Blubber layers can also be used as an energy reserve, for example male elephant seals can live off their fat reserves during summer.
The term extremities is used to mean any body part that is removed from the main body. In humans, our hands and feet count as ‘extremities’. These are often the first places to feel cold in winter. The same applies for animals. Emperor penguins have a very small bill and flippers, which means less blood is required to these areas, thus less heat is lost.
Specialised adaptations by emperor penguins
Emperor penguins are highly adapted to cold environments – and as the only animal that breeds during the Antarctic winter, they need to be. In addition to the adaptations described above, emperor penguins also have nasal chambers which recover much of the heat lost through breathing, and closely aligned veins and arteries, which enable these birds to recycle their own body heat.
As with the physical adaptations, emperor penguins have unique behavioral adaptations that enable them to survive the harsh winter. Emperor penguins form large huddles. Not only does this share body warmth, but it also shelters many of the penguins from the effects of the wind. By alternating which penguins are exposed to the wind, this benefit is shared equally amongst the group. Huddling can reduce heat loss by up to 50%.