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Activity in a Changing Climate How "warm-blooded" animals stay cool When a mammal or a bird is too hot it can do several things to cool down: Sweating This covers the skin in a layer of water. As the water evaporates it takes away some heat. Sending blood to the surface of the body
You may have noticed that when someone is hot he becomes very red in the face. This is because the body is sending blood to the skin to carry away heat. Elephants make this method of cooling even more efficient by sending more blood into their large ears. The elephant's ears radiate the heat away from the body. Panting
Not all warm-blooded animals sweat. Some cool themselves by breathing in and out very quickly. Dogs and seagulls pant. The tongue of a dog has a good supply of blood. The panting moves air over the tongue and carries heat away from the blood by conduction. Licking and bathing An alternative to sweating is used by cats and rabbits. They lick their front legs and chest. The saliva evaporates from their fur and acts like sweat does on our body. The large herbivores of Africa try to keep their bodies cool by bathing in mud or water. Moulting
Mammals are covered with hair and birds are covered with feathers. As we shall see these cover the body to keep it warm. Fur and feathers insulate the body. This is useful when the air is cold but it is not useful when the air is hot. In summer time mammals and birds lose fur or feathers so that their coat is thinner and they can stay cooler. We do not have much fur on our bodies but we do wear lighter clothes when the weather is hot. Resting Movement produces a lot of heat; if a bird or a mammal is too hot it rests, usually in the shade.
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© Paul Billiet and Shirley Burchill 2009 |
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