A well-established fact of infancy in mammals is that the mother is the primary adult with whom an infant will interact. This holds true across species, from the tiniest shrew to the most massive blue whale. However, infants of many species also interact with adults who are not their parents. This is called "allomaternal behavior" and it is commonly seen in social mammals that move in groups or herds. One such allomaternal behavior is when young females without infants of their own handle and care for infants. Young females learn to raise infants, while the mother can forage for food more effectively.