When an animal molts, it loses its feathers, fur, skin or maybe even outer skeleton. People don't molt, but plenty of animals do as a normal part of their life cycle.
Despite the guarantees made by late night advertisements, once a human is bald, he's bald forever. Not so for many animals who routinely lose and gain hair, skin or feathers. Think of shedding dogs and snakes crawling out of their old skins. This is the process known as molting. Insects that molt lose their shells or wings, often a sign that they're entering a different part of their life cycle.