New Clues Show Iceman Stayed Local

Oct. 31, 2003 -- Like a never-ending CSI episode, scientists have been scrutinizing the oldest mummy ever found with nearly all that forensic science has to offer. Over 12 years, they have learned what the man ate, his age, his health and they think they know more about how he died. Now they've answered another question — where he lived.

The latest series of tests on the mysterious, 5,200-year-old Iceman reveal the 46-year-old stuck close to home.

Hikers first found the mummified man frozen in a glacier in the Alps between Italy and Austria in 1991. Researchers have since nicknamed the specimen "Õtzi," after the Õtztal area where he was found.

To trace the ancient man's whereabouts, researchers led by Wolfgang Müller of the Australian National University in Canberra studied the different forms of elements in the Iceman's teeth, bones and intestines and compared them with types found in soil and water in the area.

They found the 5-foot-2-inch-tall man likely spent his entire life within 37 miles mostly south of the location where he was discovered. That would mean the Iceman lived most of his life in what is now Italy. His mummified remains are still in Italy — at a refrigerated museum designed just for him in the northern city of Bolzano.

Isotope for Every Age

The Iceman has revealed much about the Neolithic Copper Age of Europe. The frozen corpse was still clothed in goatskin leggings and a grass cloak, while a copper-headed ax and a quiver full of arrows were lying nearby. Now researchers say they can confidently link him with an ancient community that once settled in the region.

"I think it is important to know whether the Iceman was a chance wanderer in the Alps or whether he had migrated from farther away … or whether he was living in the local area during most of his life," said Müller. "We can now say that the latter was the case."

To reach that conclusion, Müller turned to chemistry.

Elements such as strontium, oxygen and argon occur in different forms, known as isotopes. Isotopes differ in the number of neutrons they carry in each atom. By comparing the ratio of one isotope found in the water or soil of a region to that found in the body tissue, researchers can locate the source of the Iceman's food or water and link him to that region.

Isotopes in Õtzi's teeth reveal where he spent his youth, since dental enamel is fixed at the time that the tooth is formed. Isotopes in his bones reflect where he spent most of his adult life, since bones are remineralized every 10 to 20 years. And isotopes taken from the mummy's intestine shed light on where he spent his final hours.

Müller and his colleagues also analyzed the chemical makeup of minerals that had been leached into Õtzi's water supplies to try and further narrow down his stomping grounds.

"It's a 'you are what you eat' type of thing," said Henry Fricke, a geologist at Colorado College in Colorado Springs who co-authored the recent analysis of the Iceman in today's issue of Science. "You incorporate elements from food and water and that's incorporated into your tooth enamel and bones."

Since the Alpine mountains around where the Iceman was found host minerals with a range of distinctive elements and isotopes, it was possible to link Õtzi with very specific locations.

Valley to Valley

Oxygen isotopes from Õtzi's tooth enamel matched those found in valleys just south of where he was found. And in fact, Fricke and Müller suggest that an archaeological site of a small Neolithic village in the nearby Eisack Valley may very well be where Õtzi spent his youth.

Isotopes and minerals from the Iceman's thighbones reflect those found in soil and water between the more northern location where he was found and his childhood one, suggesting he roamed at a slightly higher altitude as an adult.

To determine where the Iceman spent his final days, Müller's team analyzed argon found in white mica from Õtzi's intestines that could have come from a grinding stone used to mash the wheat that he had eaten just hours before his death.

The mica matched pieces found in the Etsch Valley, a region west of the Iceman's assumed childhood home. All locations fall within a 37-mile area.

So if Õtzi spent his life close to home, what was he doing in the mountain peaks on that fateful day?

Bloody Battle

Theories about how the Iceman died have varied wildly since his discovery, but some evidence suggests foul play.

Scientists first believed Õtzi may have been a shepherd who was returning with his flock when he encountered some kind of trouble, hurt his ribs and then fled to the mountains to escape. Then, overtaken by exhaustion, Õtzi propped his copper-headed ax against a rock and lay down or collapsed.

Analysis of Õtzi's bones show he suffered from arthritis and so may have needed a rest after scrambling to the alpine ridge where he was discovered.

In 2001, scientists X-rayed the mummy's body and made a shocking discovery: The radiologist noticed what looked like a dense object in the body's shoulder. Further scrutiny showed it was an arrowhead lodged deep inside his shoulder.

One of the first to see the frozen mummy in the alpine glacier later revealed that it appeared Õtzi was clutching a knife in his right hand when he was found. Further analysis showed Õtzi had a deep wound in the same hand and had traces of blood from four different people on his clothes and weapons.

All of these revelations cleared away previous theories that the Iceman might have fallen asleep and died of hypothermia. A new picture emerged suggesting he was attacked and fought back with a hand knife. He eventually fled but was struck by an arrow as he ran away. He reached the top of the mountains, but was exhausted and bleeding and collapsed on the ground, and there he lay for more than 5,000 years.

That's the story for now anyway.

As scientists are learning, the Iceman holds seemingly endless clues, and theories about his life and death could evolve as forensic tools designed to catch new clues improve.