Weaning

Weaning means changing the diet of a baby little by little, from its mother's milk to the food it will eat as an adult. Since only female mammals make milk, weaning is only a necessary process for mammals. When a baby does not drink any more breast milk (or milk substitute), the baby has been weaned.
Human weaning.
Human babies should start eating small amounts of solid food, along with breast milk or formula, when they are about six months old. Before this time, a child's digestive system and kidneys are still forming, so the child is not ready for solid food.
Babies do not have teeth and cannot chew their food, so they are usually fed soft, runny food such as cooked mashed fruit or vegetables. Babies cannot digest some foods which adults can eat, including food with nuts or with large amounts of gluten, salt or sugar. Also, babies' digestive systems are very sensitive to bacteria, so they should not eat any foods with honey, eggs or shellfish in them because these foods sometimes contain bacteria.
Weaning conflict.
Weaning conflict happens when the mother wants to wean her baby, but the baby wants to keep breastfeeding. The mother tries to force the baby to stop breastfeeding, and the baby tries to force the mother to continue. Some evolutionary scientists think mammal mothers need to wean their babies as soon as possible, so they will have a greater chance of having more babies and spreading their genes. But mammal babies want to breastfeed as long as they can so they will have a chance to grow strong, and also to enjoy the full care of their mothers. Weaning conflict happens in several mammal species, including primates and canines.