Mad About Science: Bog bodies

By Soncirey Mitchell
Reader Staff

This subject isn’t for the squeamish, dear reader. Proceed with caution.

Plant-lovers will recognize peat as the light soilless medium sold at garden stores and used to add acidity to soil, manage moisture or start seeds. Others may know peat as the centuries old, carbon-inefficient fuel source sometimes used to heat houses, cook and even generate small amounts of electricity.

The most fantastic and bizarre thing about peat, however, is its ability to perfectly preserve dead bodies under the right conditions. Peat is a buildup of partially decomposed plant matter — mostly sphagnum moss — found in bogs around the world. Throughout northwestern Europe, it’s not uncommon to uncover mummified corpses, often called “bog bodies,” while harvesting the peat for the aforementioned reasons. The best preserved specimens still have their hair, skin and clothing despite many of them being more than 2,000 years old.

Very particular circumstances must align to achieve this level of preservation. The best bogs receive moisture exclusively from precipitation, rather than groundwater, which allows them to trap the decaying plant matter in an acidic, nutrient-poor and mostly oxygen-free — or anaerobic — environment. In this harsh environment, microorganisms like bacteria that require oxygen can’t properly decompose the bodies.

The acidic, watery bog eventually pickles the corpses. If that weren’t enough food for thought, the sphagnum produces sugars that act as tanning agents, turning the skin and muscle into leather.

They also bind calcium to nitrogen, thereby drawing it out of the bones. The resulting decalcified bones take on a rubbery consistency. If you’ve ever soaked an egg in vinegar until the eggshell dissolves, you’ve already seen this process in action. In some bodies, the bones are practically nonexistent.

The Tollund Man bog body. Photo courtesy Museum Silkeborg.

The most famous bog bodies have rubbery or missing bones that leave them looking shrunken and deflated. In contrast, bodies found in calcium and nutrient-rich bogs fed by groundwater do not produce the anaerobic environment needed to preserve soft tissue. In these bogs, only the skeletons remain.

The Tollund Man, a body discovered in Denmark in 1950, was so well preserved that police mistook him for a recent murder victim. Through modern carbon-dating techniques, archaeologists have recently concluded that the Tollund Man died anywhere from 405-380 B.C.E. at the approximate age of 40. Like many bog bodies, he would have lived during the pre-Roman Iron Age.

Analysis of the Tollund Man’s stomach contents revealed a last meal of hulled barley, flax, false flax and two types of knotweed. He was also infected with several kinds of intestinal parasites — including tapeworms — which he would have picked up from contaminated food or water.

The Museum of Silkeborg in Denmark displays the Tollund Man’s head alongside a reproduction of his body as it looked before scientists allowed it to dry out. To preserve his head, they had to replace the bog water that had kept his cell’s hydrated for thousands of years. First they saturated the head in alcohol, then toluol — a common ingredient in varnishes and paint-thinners — then liquid paraffin wax and finally bees’ wax.

The British Museum preserved the Lindow Man, another bog body, by immersing him in polyethylene glycol to prevent him from shrinking. They then swaddled the body in plastic wrap like a leftover sandwich, froze and then freeze dried him.

It’s unclear how many bog bodies have been exhumed over the years. Personal written accounts, police reports and newspaper articles are the only evidence of some older finds, as the bodies have since been buried in local cemeteries, lost or returned to their bogs. These accounts put the total number of discovered bodies at nearly 2,000 — though the actual statistic is likely far lower. The bodies that did make it into the hands of scientists mostly date from the Late Nordic Bronze Age from 1100-500 B.C.E. to the Pre-Roman Iron Age from 500-1 C.E.

Archaeologists and anthropologists have long puzzled over why these bodies ended up in the peat. The Lindow Man, Tollund Man and many more met exceedingly violent ends and experts agree that they were intentionally placed into the bogs after their murders. However, the purpose and extent of the violence is still debated.

The popular view among scientists and laymen is that the bog bodies were victims of human sacrifice. This hypothesis stems from the incredible number of wounds — made by a variety of weapons — found on many of the bodies. The degree of overkill suggests that their deaths were ritualistic or in some way symbolic. This hypothesis remains prominent, although recent CT-scans revealed that some of these wounds were actually caused by diggers harvesting peat or the weight of the bog compressing the bodies, not by ancient hands.

There are many competing hypotheses as to why the victims were killed, and we can’t justifiably apply one single idea to every death.

The individuals may be executed criminals or possibly scapegoat figures. In the latter hypothesis, the victims symbolically embodied their community’s guilt. By sacrificing the individual, the surviving members freed themselves from any past transgressions. Proponents of this idea believe that the sacrifices were chosen because of their visible disabilities, like the Kayhausen Boy, who had an infected hip socket and therefore had difficulty walking.

Critics caution that this hypothesis could be anachronistic and reflect modern ideas of eugenics more than the actual beliefs of ancient people. An alternative hypothesis agrees that the individuals were chosen because of their physical differences, but instead suggests that disabilities were considered evidence that an individual was marked by the gods as a worthy sacrifice.

For now, the exact nature of Europe’s bog bodies remains a mystery.

Stay curious (and out of any peat bogs), 7B.

Brenden Bobby will be back next week when he returns from his much deserved mini-staycation.