REASON FOR THE SNAKE REMOVING ITS SKIN:
Monthly once, our skin cells fall down. In 60 days, all the old blood cells dye and new blood cells grow all the cells of the all the organs of the body, except the brain cells are renewed then and there.
Likewise, for snakes, its cells are renewed. In our skin, cells which are here and there fall and new cells are generated. That is why; we are not feeling about this. But, snakes like creatures change the old skin once in a particular period, like we change the old shirt and wear new shirt. As snakes grow longer, its skin enlarges. When the skin cannot enlarge further, the snake grows its new skin under the old skin.