Only about 100 cases are documented around the world. The true human tail upon birth is caused by a lack of cell destruction of the distal end of the embryonic tail.
According to some experts, the true human tail is not really a tail at all. It is thought to be linked to spina bifida or a hiccup in the natural human development process. While others thing that it is due to mutation of the genes that produce cellular destruction of the tail component
As it is well known that it is derived from the most distal remnant of the embryonic tail. It contains adipose and connective tissue, central bundles of striated muscle, blood vessels, and nerves and is covered by skin while it lacks Bone, cartilage, notochord, and spinal cord. The true tail arises by retention of structures found normally in fetal development. It may be as long as 13 cm, can move and contract, and occurs twice as often in males as in females. A true tail is easily removed surgically, without residual effects. It is rarely familial.
The longest known tail is 13 inches long and belongs to a man in India.
