Weaning is the process of gradually introducing a mammal infant, either human or animal, to what will be its adult diet and withdrawing the supply of its mother's milk. The process takes place only in mammals, as only mammals produce milk. The infant is considered to be fully weaned once it no longer receives any breast milk (or bottled substitute). Normally, at the end of the weaning process, mammals experience reduced lactase production, becoming lactose intolerant. This is estimated to be th… (More on Weaning)