The receding forehead was a natural characteristic of the people of ancient South America and has also been found in fossil skulls. This elongated head was present even in the fetus of the Peruvian mummies. Some scientists believe it was impossible to deform a human head to such proportions and point out that the mass of these skulls is twice that of an average human skull. This leads the UFO community to believe that the skulls are not human but extraterrestrial in origin or by aliens inbreeding with humans.
Bibliography
Atlantis: The Antediluvian World, Ignatius Donnelly,1882, Gramercy Publishing Company, New York.
