Everyone has a navel. Some are large, some small, some are shallow, some deep. The size and shape make no difference, however, because the navel actually serves no purpose at all. Lots of parents have a nickname for the navel-the belly button. But I’ll bet you don’t know the name your doctor gives it. He calls it the umbilicus.
The navel is the scar left behind after the umbilical cord has been tied and allowed to drop off. In unborn infants, the cord is about three feet long and about half the thickness of a garden hose. This cord attaches the unborn baby to its mother’s uterus inside her body. Through it, the unborn child gets all of its nourishment and all the oxygen it needs. When the child is born and comes out of its mother’s vagina, part of the umbilical cord comes out too. The doctor immediately clamps and cuts the umbilical cord a couple of inches from the baby’s stomach. The cord is no longer necessary because the baby breathes air through its own lungs. As a result, it doesn’t need to get oxygen from its mother through the umbilical cord. Then, a few hours after childbirth, the infant is fed by a bottle or from its mother’s breast, and so doesn’t have to get nourishment any longer through the umbilical cord.
Animals that develop inside their mother’s uterus also have umbilical cords which the mother animal bites off at birth. Most animals are so smart they don’t need doctors when they have babies.
After the baby is a few day’s old, what is left of the umbilical cord dries up by itself and falls off. And what is left is the belly button, or navel.