Investigations of prehistoric burial sites in Europe show that the region's population may have practiced ritual human sacrifice.
The large number of multiple-burial sites, some containing skeletons of dwarfs and deformed children accompanied by ornate grave goods, suggests that human sacrifice was a custom in Europe between 28,000 and 10,000 years ago, says biologist Vincenzo Formicola of the University of Pisa in Italy.
"These findings point to the possibility that human sacrifices were part of the ritual activity of these populations," writes Formicola.
Three multiple-burial graves in Russia, the Czech Republic and Italy are the focus of his findings, published in the scholarly journal Current Anthropology.
A grave in Russia reveals the skeletons of a boy and girl, thought to be between nine and 13 years old, lying head to head alongside spears of mammoth tusk, hundreds of fox canines and thousands of ivory beads. The skeleton of the girl shows evidence of a congenital disease.
Formicola believes that the beads were made specially for the children, because of their small size compared to beads found on an adult male at the same site. Rich burials traditionally suggest high status, Formicola writes, and "it is hard to imagine this kind of motivation for two children."
"The enormous amount of time required to prepare all those ivory objects and the possibility that ivory beads were made specifically for the two children by a few specialists would imply that those grave goods were ready when the two children died, which in turn leads one to wonder whether this ceremony was foreseen long in advance," writes Formicola.
Rupert Housley, a professor of archaeological science at the University of Glasgow, suggested there may be other explanations for the unique burial. The beads may have been family heirlooms, prepared years earlier for a person of high status and incorporated into the graves of the children.
Housley, who is conducting a study in southern Russia on the connection between Neanderthals and modern humans, said multiple-burials were common in that period and many children died at a young age.
"Diseases could explain children dying at the same time, and then being placed at the same burial site. So if one is going to invoke sacrifice on the rest of it, it's a possible explanation but there are also others," said Housley. "I would entertain the idea but it is only one of many possibilities."
The site in the Czech Republic holds three skeletons of bodies aged 16-25, two males and one deformed individual the sex of whom has not been determined, according to Formicola. One lies face down, and another lies on its side, reaching toward the pubic area of the deformed skeleton.
At a site in Italy, a female skeleton appears to be holding a dwarf, aged 17, whom Formicola suggests may have received a special burial because of his physical condition.
"Elaborate burials, selected individuals, rich ornamentation, and site of inhumation continue to raise questions... and stimulate reflections about social organization, conceptions of life and death, and the perception of diversity," writes Formicola.
Housley said that evidence of cannibalism has been found at sites 12,000 years ago in the same area, so if Formicola's conclusions are correct it could be part of a pattern.