Molting, shedding of the skin, fur, or feathers by an animal. It may be a seasonal occurrence, as a periodic renewal of fur or plumage in mammals and birds, or it may be associated with growth, as in insects or crustaceans. In birds and mammals the molt is primarily to renew worn fur or feathers so that pelage or plumage is kept in good condition for waterproofing, insulation, or flight. It also may serve to shed breeding plumage or to change between summer and winter coats. In invertebrates the rigid external skeleton must be shed and replaced to allow growth within. In larval insects the final molts are involved in the metamorphosis to adult form.