How do animals cope in extreme cold?

Animals that live in extreme cold are often larger than similar animals in other climates: a big body can produce and keep heat more easily than a small one.

Seals and whales have a thick layer of fat under their skin - it''s called blubber.

It keeps them warm in the ice-cold water, since fat is an excellent insulator.

Other animals have thick fur or downy feathers to keep them warm.

Penguins are a good example for animals adapted to the cold: they have a layer of protective fat and three layers of water-proof plumage. In winter they huddle together in large groups to keep warm.

How do animals cope in extreme heat?

Many animals living in extreme heat - for example in the desert - have adapted their daily routine to the climate by living in burrows and only coming out when it''s dark.

Many desert animals are also smaller and lighter-coloured than their relatives from other climates - a light colour reflects the heat rather than absorbing it.

They tend to have long ears and tails: The enormous ears of jackrabbits, for example, with their many blood vessels, release heat when the animal is resting in a cool, shady location.

Another example of this phenomenon are penguins who live in warm climates and who tend to get too hot.

Their fins are bigger than the ones of their Antarctic cousins, so that the heat has a larger surface area to dissipate from.