Ötzi the Iceman's stomach wasn't where it was supposed to be. The misplaced organ eluded researchers for some 20 years. But in 2009, while looking at new radiographic scans, they finally found it—inexplicably pushed up under his ribs, where the lower lungs usually sit. What's more, it was completely full.

Since 1991, when a pair of hikers found the 5,300-year-old hunter in the Ötztal Alps, researchers have been scouring Ötzi's frozen, shriveled form for clues to life in the past and his violent demise. They've studied his sheepskin coat and goat skin tights; scrutinized his tooth decay; ogled his likely frostbite-induced nub on his toe; ruminated over parasitic worm eggs in his gut; and cataloged every tattoo inked on his skin.

And now, after putting the stomach contents through a battery of tests, the researchers determined the ice mummy's final meal: dried ibex meat and fat, red deer, einkorn wheat, and traces of toxic fern. The results, published this week in the journal Current Biology, offer a stunningly detailed peek into an ancient diet and hint at possible food preparation methods.

The Lost Stomach

In the late 90s, with Ötzi's stomach nowhere to be found, researchers studied the nitrogen isotopes of the mummy's hair for dietary clues, which suggested the Iceman was a vegetarian. Later analysis of his colon contents pointed to Ötzi's omnivorous ways, revealing he ate not only cereals but also red deer and goat meat in the day before his death.

But in this latest work, scientists were trying to figure out the exact species that made up the Iceman's last meal. And to do that, they had to sample his stomach.

Iceman Autopsy Watch an examination of the 5,000-year-old Ötzi unfold in this time-lapse video.

They located the wandering organ by examining Ötzi's gall stones, which form in the gallbladder, a small sack sitting below the liver near the stomach. By lining up the position of surrounding organs in radiographic images, the team finally found the stomach.

To sample it, however, scientists had to first defrost the mummy, which is kept at a chilly 21.2 degrees Fahrenheit to prevent microbial invasion. They then used an endoscopic tool to pull 11 blobs of brownish yellow material from his stomach and intestines.

Unlike the mushy intestinal material, the crumbly stomach stuffs were essentially freeze dried, study author Frank Maixner explains. “It has an interesting appearance, actually,” he says.

The research team first took a peek under magnification. “Already under a microscope it was clear it was an omnivore diet,” says Maixner, who is a microbiologist at the Institute for Mummies and the Iceman in Bolzano, Italy. Tiny flecks of undigested fibers of plants and meat were visible in the sample, surrounded by a cloudy haze of fat. The team then began their array of tests, which included DNA, proteins, lipids, metabolites, and more.

View Images A tiny piece of undigested plant tissue researchers spotted in the Iceman's stomach contents. Photograph courtesy Institute for Mummy Studies, Eurac Research/Frank Maixner

Ötzi's Last Meal

Lipids and protein analysis indicate that Ötzi was eating both muscle and fat of the ibex (Capra ibex), a goat still common in the Ötztal Alps. The high-fat stomach contents would have supported energy-intensive treks. “Even though maybe ibex fat tastes horrible,” Maixner jokes.

But curiously, though DNA analysis suggests red deer (Cervus elaphus) was also part of the meal, researchers couldn't figure out what part of the creature Ötzi ate. One possibility is that he consumed its organs, like the spleen, liver, or brain. Degradation may also be an issue. “It's really hard to say,” Maixner says.

They could, however, look at meat preparation. By studying the meat's microstructures and chemistry and comparing it to modern cooked and uncooked meats, they surmised Ötzi's meat was not heated above 140 degrees Fahrenheit. It's most likely the meat was dried for preservation, Maixner says, since fresh meat spoils quickly. The presence of carbon flecks also hint the meat could have been smoked.

Ötzi also ate einkorn wheat and the toxic bracken fern. When eaten in sufficient doses, bracken has been associated with anemia in cattle, and blindness in sheep. It may also have carcinogenic effects. Yet some people still eat small quantities of the plant.

It's possible Ötzi also indulged in this greenery. “ You can go as far as he might have treated stomach ache with this fern since we knew that he suffered from some stomach pathogens,” says Maixner. But he adds, “this, for me at least, goes a little bit too far.” Another possibility is that he wrapped his food in fern, accidentally ingesting pieces along with his snack—an idea previously proposed for Ötzi's ingested moss.

Peeking at the Past Through Ötzi's Stomach

Together, the diet shows a well-prepared meal, with some fiber, protein and lots of energy-rich fat. “They had knowledge on making preparing the proper clothes, the proper hunting equipment, and this is also true for the diet,” Maixner says. “They were clearly well prepared.”

Though it's just a single sample, the results give a surprisingly detailed look into Ötzi's final hours. “I don't know if we're going to get a whole lot better than this,” says Katherine Ryan Amato, a biological anthropologist at Northwestern University who wasn't involved in the work.

Researchers have long used indirect methods to look at diet, broadly looking at transitions through time, she explains. “This actually lets us get at it on a finer scale and talk about it in more detail,” she says, “which is really exciting.”

The events surrounding Ötzi's death are still debated. His many recent wounds point to violent conflict, and some say Ötzi fled into the mountains while being hunted down. But Maixner says that the last meal points to a slightly different story: “I personally think he was prepared for this trek.”