Случаи, когда младенцы рождались с хвостом, known for a long time and have been repeatedly described. Hundreds of years ago, the tail of a European man caused superstitious fear, and the fate of unfortunate tailed babies, recognized as servants of the Devil, was sad.
People’s tail is an atavism, it’s notas functional as small monkeys. To do this, it must be present muscles and vertebrae, but they are not. It is formed by germinal tissue in the event that the development of a human embryo slightly deviates from the norm, and this happens rarely. At the same time, the tail of a person as an atavistic process is a clear evidence that the long ancestors of homo sapiens had a tail, no doubt.
Why did they lose him?Look at the behavior of small monkeys (macaques, monkeys). The tail plays for them the role of the fifth hand. He is strong enough to withstand their low weight while freeing limbs. With increasing monkey body weight, the muscle thickness of the tail rapidly increased until it became a hindrance to existence in conditions where it did not take long to hang on the trees.
It used to be that a man with a tail inthe embryonic state reflects the process of evolution: from the intestinal cavity hydra - through the stage of fish with gills - through the stage of an animal with a tail - to, in fact, man. Serious scientists were convinced that this irrefutably proves Darwin's theory of the origin of man from the animal world. This is true, but the development of the embryo has nothing to do with it: from the very first day of his life he is just a human being and no one else.