Discovered in a bog in Denmark in 1950, Tollund Man had been hanged. His last meal was a porridge of flax and barley. Image credit: RV1864 via Flickr // CC BY-NC-ND 2.0

Here in America, we largely think of bogs as those things in New England that produce the perpetual Thanksgiving dinner staple, cranberries. But bogs are a much more important geographical feature in Northern and Eastern Europe, and have been for centuries. They are especially useful for archaeologists, though, because of their excellent preservation of organic materials, including massive wads of ancient butter and chunks of leathery human bodies.

Most of the discoveries of ancient remains in European bogs have been the result of modern peat harvesting. Composed of vegetation like sphagnum moss that has decayed over time, peat can be burned and used as a fuel when dried. But peat in a wetland environment can also create anoxic—or oxygen-free—conditions that slow the decomposition of organic remains in the bog. The combination of cool climate and anoxic water in these northern bogs makes conditions right for long-term preservation.

In the past few years, numerous examples of “bog butter” have come out of the peat in Scotland and Ireland. These usually stinky chunks of yellowish glop can weigh up to 50 kg and are generally found in a wooden container or animal skins for protection. Dating back as far as 5000 years ago, some of the butter is made out of dairy fat, and some of it is made from lard or tallow, according to recent isotope testing done on some samplesThe most recent “bog butter” find came from County Meath, Ireland, in June. Butter was ubiquitous in many past eras, acting not only as a food but as a salve for wounds and a substitute for cash in paying taxes, so it’s also possible it was buried to protect a family’s wealth from thieves.

A man demonstrates how to cut peat with a slane, or turf spade, in Ireland's Blackwater Bog. Image credit: Joseph Micshyshyn via Wikimedia Commons // CC BY-SA 2.0

As weird as it must be to find a hunk of rancid butter the size of a small child while going about one’s work, imagine finding hunks of leathery human body parts instead. Those also come out of European peat bogs with considerable regularity but are decidedly less gelatinous.

Bog bodies are, quite simply, humans whose remains have been preserved in a peat bog. Just as the bog’s cool, anoxic environment can preserve butter, it can also preserve people. And while these people are technically natural mummies, their bodies aren’t like traditional desiccated mummies from Egypt or freeze-dried mummies from the high Andes.

The secret is once again in the peat. Many peat bogs have highly acidic water, which actually works to dissolve the skeleton by leaching out the calcium phosphate in the bones. But the skin and organs are preserved thanks to the lack of oxygen. Because of the tannins, a chemical compound in the peat, the skin becomes brown and leather-like, and the result is a human-shaped skin bag that retains astonishing detail—fingerprints, whiskers, wrinkles.

Bog bodies date to as early as 8000 BCE and as recently as World War I, in the case of some Russian and German soldiers who died fighting in a lake district in Poland. While a study in the mid-20th century claimed to have found nearly 2000 bog bodies, researchers today count only about four dozen that are intact and with appropriate archaeological context. And the vast majority of them are from the Iron Age of Europe—around 900 BCE to Roman contact in the 1st century CE. This time period coincided with an increase in weaponry and violence throughout the region.  Interestingly enough, bogs can also contain iron, and many objects were smelted in this period from “bog iron.”

Just as most of the bog bodies date to the same general time period, many share similarities in the people’s deaths and circumstances of burial. Take the three most famous bog bodies: Tollund Man (4th century BCE), Grauballe Man (3rd century BCE), and Lindow Man (1st century CE). All were found mostly or completely naked with evidence of having met violent ends.

The best studied of all the bog bodies, Tollund Man was initially thought to have been a modern murder victim when he was found in 1950 in Denmark. A lack of clothing (save for a felt hat and a belt) was odd—but not as strange as the remains of a noose around his neck. Forensic scientists who examined the body in 2002 found that Tollund Man’s tongue was distended—an indication he had been hanged. The stubble on his face suggests Tollund Man didn’t shave for at least a day prior, and analysis of his gut contents revealed a meal of barley and flax porridge eaten 12 to 24 hours before death.

A couple years later, Grauballe Man was found, also in the Jutland peninsula of Denmark. Unlike Tollund Man, Grauballe Man was completely naked. His shock of red hair looks almost like a wig, the result of discoloration from the bog. No noose was found with this body; rather, his neck had been slit open so violently that his trachea and esophagus were severed. Grauballe Man’s remains actually include bones, which are occasionally preserved in bogs. He was likely an older adult, based on the degeneration of his spine, and his teeth suggested his childhood involved periods of poor health.

Grauballe Man's hand. His remains are on display at the Moesgaard Museum, Denmark. Image credit:  Malene Thyssen via Wikimedia Commons // CC BY-SA 3.0

Over in England, Lindow Man was discovered in 1984, becoming the most complete bog body discovered in that country. He wore a fox-fur armband, but otherwise was completely naked. And his death was perhaps the most violent of all known bog bodies. First, he was clocked on the head with a blunt object; he may have fallen unconscious but didn’t die from that, as there is evidence of slight healing in the wound. He was stabbed in the chest but also strangled with a sinew cord that was recovered with his body. Other wounds include a broken rib and broken neck vertebrae, but with archaeo-forensic cases, it is not always possible to tell which injuries happened when. Lindow Man appears to have eaten charred bread as his last meal.

There is clearly a theme to most of these Iron Age bog bodies—extremely violent ends. Other examples of murdered men thrown into ancient bogs include: Dätgen Man from Germany, who had been beaten, stabbed, and decapitated; the Nieuw-Weerdingen men from the Netherlands, one of whom had been disemboweled; and Old Croghan Man from Ireland, whose nipples had been cut out, possibly as a way of torturing him before death. 

There's little left of Old Croghan Man, but there's enough to indicate that the Iron Age man may have been tortured. Image credit: Mark Healey via Wikimedia Commons // CC BY-SA 2.0

They weren’t all men, either. One of the Borremose Women from Denmark was discovered with a belt around her neck and an infant in her arms. “Moora” from Germany is mostly skeletonized, but she was malnourished and had suffered two skull fractures before her death. And Kayhausen Boy from Germany was around 7 to 10 years old when he was stabbed repeatedly in the throat and arm. Especially poignant was his infected hip socket, which would have disabled him and caused him pain at the end of his short life.

The real question that’s been haunting archaeologists since the bog bodies started to be uncovered in the 19th century is: Why were all these people murdered? There aren’t yet any definitive answers, in particular because bog bodies span nearly 10 millennia and much of a continent. Any explanation for violence and burial in the past has to be based in large part on culture, and culture changes dramatically over time and place.

For the most part, archaeologists have advanced two general theories for the murder of the bog bodies. The much earlier Bronze Age bodies are thought to have been potentially human sacrifices, particularly because many of the people were adolescents and young adults when they were killed.

The second theory concerns the Iron Age bodies, which may have been those of criminals or other people considered socially deviant. Artifact evidence suggests that bogs may have held ritual significance since they are an interesting geographical feature: neither solid land nor open water. During a tumultuous time just prior to prolonged contact with the Romans, where northern European groups began to see the start of hierarchy and social class differentiation, perhaps ignominious burial in a bog was Iron Age people’s way of separating “us” from “them.”

Unearthed in the Netherlands in 1897, Yde Girl had a noose wrapped around her neck and a stab wound near her collarbone. She was about 16, had scoliosis, and stood 4' 6". Image credit: Bullenwachter via Wikimedia Commons // CC BY-SA 3.0 

While most bog bodies were found in the 19th and early 20th centuries owing to the role of the peat industry in fuel production, a renewed interest in peat in Ireland has meant half a dozen bog bodies have been discovered there since 2000. These, plus new studies of well-conserved bog bodies found decades ago, are giving us new insight into life in northern Europe in the first millennium BCE.

Contemporary techniques to analyze the bodies include 3D CT scanning, which doesn’t destroy the skin the way that traditional autopsy would. The diet of the bog people is being reconstructed through carefully extracted gut contents and chemical analysis, revealing varied diets with a lot of grain and local seeds. And thanks to preservation by the peat, the bodies are also revealing their parasites. Every single bog body that has been directly examined with modern techniques had a parasitic infection, usually roundworm or whipworm. Life before antibiotics was rough indeed.

One thing that archaeologists are still lacking, however, is high-quality DNA from the remains. Although Grauballe Man was tested for ancient DNA, his body did not produce any, probably because the acidic conditions in the bog damaged the proteins on which ancient DNA testing is typically done. As this technology is progressing rapidly, it is only a matter of time until the bog bodies’ DNA gives us deeper insights into their lives.

But all of this information is still coming from individual remains. Unlike with bioarchaeological research, which uses hundreds of skeletons from one cemetery to understand whole populations of past people, bog bodies are still found in isolated contexts, purely by chance. The recent finds in Ireland, however, speak to the potential for more bog bodies to surface in the second half of this decade. When they do, archaeologists and forensic specialists armed with the latest techniques will be on hand to coax new clues from the depths of the bog.