Vestigial Human Tails
In the earliest stages of development of a human embryo, it has a little tail. This tail measures about 1/6th the size of the entire length of the embryo (the equivalent of a 12-inch tail on a 6-foot man). But as the fetus develops, the tail is absorbed. Enzymes dissolve the bones, and the entire structure retracts into the fetus's body.
Sometimes, for a variety of reasons, a baby is born with its vestigial tail still attached. According to the National Institute of Health, "There have been 23 vestigial tails reported in the literature since 1884," or approximately one baby born with a tail every 5 ½ years.
