The term moulting is used to referto the entire cyclical process of preparing for, undergoing, and recoveringfrom the old shell. Since the shell is hard and inelastic, it mustbe shed periodically in order for the animal to grow. It is common for the members of Arthropoda (Insects, Crustaceae etc.).Birds and mammals moult for the new feathers, hair, or skin to make way for a new growth. This moulting is energeticallyexpensive and leaves the animal temporarily vulnerable to predators and other dangers.