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Science of Animals

'Men and 'Animals' coexist on our earth. The curiosity in man made to study the behaviour of animals scientifically. This study has become a Science in his daily life.

How does a chameleon (Oosaravelli in Telugu) change its colour?
'Oosaravelli' is a kind of lizard which we find in gardens and forests. Which changes its skin colour according to its feelings and also the temperature of the surroundings. The chameleon changes its skin colour to match the surroundings in order to escape detection by an enemy.

The skin of every animal consists of cells which contain coloured substances called pigments. These substances give colour to the skin. In chameleon the colour cells lie in three layer under its transparent skin. The outermost layer consists of yellow and red pigments and in another layer there will be crystals which can reflect blue and white light. The innermost layer contains the black pigment called 'melanin'.

When the chameleon is completely relaxed, melanin granules will be in the lowest layer while white light is reflected from the middle layer and the chameleon looks yellowish or reddish when the melanophores are stimulated, the granules rise up to the middle layer and white light is not reflected and the chameleon emits the mixture of blue and yellow and appears green. When the chameleon is still more excited, the black granules will come up to the surface and the chameleon appears dark brown. Thus the chameleon changes colour according to its feelings like fear, anger etc.,

People who will not stick to any particular ideology and changing their opinions after are called chameleons (Oosaravellis).

Why 'Dogs' are found panting with their tongues out?
Dogs just like elephants, cows and human beings are not only mammals but also warm blooded. Warm blooded means having a constant body temperature even when the temperature of the surroundings change.

The normal temperature of our body is 37°C. If our body temperature rises even by one degree we feel uncomfortable. How our body maintain we feel uncomfortable. How our body maintain a constant temperature? for example, in summer, when it is too hot, our body temperature rises. At the same time we sweat. The sweat produced in the sweat glands under our skin comes out through the small pores in the skin. This sweat evaporates by taking the extra heat obtained by the body from the surroundings. As evaporation causes cooling we feel cooler and better. Thus our body looses the extra heat obtained in summer through sweat and maintains the body temperature always to be normal and constant.

But all mammals, for example 'Dog' cannot use this method to keep its body temperature constant. Dog has few sweat glands and hence it has to use some other method of controlling its body temperature. It does so by panting, with its tongue hanging out of its open mouth. When a dog pants, it takes in air through its nose and gives it out through the mouth. During this process the saliva in its mouth and on the tongue evaporates which causes cooling and the dog feels cool and comfortable while its body temperature is constant and normal.
Lakshmi Emani
Published date : 02 Oct 2012 01:08PM

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