Scientists solve iceman mystery

The prehistoric man, known as Ötzi, never roamed far from the glacier that preserved him swissinfo.ch

Some 5,200 years after a prehistoric man was frozen in an Alpine glacier, scientists in Switzerland and Australia have determined where he came from.

By studying his bones, teeth and intestines, researchers are now convinced that they know where the Neolithic mummy, also known as Ötzi, lived and travelled.

“The evidence points consistently to the view that he came from south-east of the site where he was found on the Austrian-Italian border, and that he migrated north and west over his lifetime,” said Alex Halliday, who heads the institute for isotope geochemistry at the Federal Institute of Technology in Zurich.

“Some people had previously proposed that he came from further north or locations close to where he was found.”

Fingerprint

Isotope geochemistry depends on the fact that most elements in our Earth have several different isotopes.

Isotopes are atoms of the same element. They have the same number of protons but different numbers of neutrons which means they differ in mass. By measuring the proportion of one isotope to another, scientists get clues as to where an object formed.

Through food and drink, isotopic signatures from local rocks and rivers transfer to the biominerals deposited in the bones and teeth of the living body.

The researchers compared isotopes of a variety of elements in the Iceman’s teeth, bones and intestines to the isotope signatures in the soils and waters of the region to determine where he lived at various stages in his life.

They concluded that Ötzi probably spent his entire life within a 60-kilometre range south of the glacier that preserved him.

“We can use early tooth material which started to grow at an early stage in Ötzi’s life and use that to infer where his childhood was,” said Halliday.

“We can then use some of the bone material which mainly reflects later growth in his life to try and infer where he migrated to, and then we can actually look at some of the food content in his stomach to tell us where his last meal came from.”

Childhood

The study restricts the Iceman’s birthplace to a few valleys near the borders of Italy and Austria based partly on inferences about the water he drank as a child.

“The oxygen isotopic composition of his tooth enamel reflects the oxygen isotopic composition of the water he was drinking and that changes with elevation and rainfall conditions,” said Halliday.

Wolfgang Müller, formerly based in Zurich and now at the Australian National University in Canberra, Australia, led the international team, piecing together a picture of Ötzi’s migration.

Scientists in the United States and Britain participated in the study which also examined the Iceman’s implements and clothing.

Based on their findings, the authors suggest that the Alpine valleys of central Europe were permanently inhabited as the Stone Age drew to a close.

swissinfo, Vincent Landon

Key facts

Ötzi’s body was discovered by hikers in the Schnalstal glacier high in the Italian Alps in 1991.
He was named after the Ötz Valley where his body was found.
His body is kept in cold storage in the South Tyrol Archaeological Museum in Bolzano, Italy.