The same people that built Stonehenge left evidence of parasitic infection in their fossilized stool.
Analysis of ancient coprolites -- fossil feces -- at the Durrington Walls site, 2.8 km from Stonehenge, gives us a snapshot into the lives and diets of the people that erected this famous landmark. The coprolites, dating to around 2500 BC, revealed that the winter feasting customs of the inhabitants at Durrington Walls included the consumption of internal organs from cattle. The presence of specific parasites in these coprolites shows that these items were sometimes consumed raw or undercooked and that leftovers were fed to the dogs of the group.
Building on a full belly
"This is the first time intestinal parasites have been recovered from Neolithic Britain, and to find them in the environment of Stonehenge is really something," said study lead author Dr Piers Mitchell from Cambridge's Department of Archaeology.
Durrington Walls was occupied on a seasonal basis, Dr Mitchell explains, mainly over the winter, at the time that Stonehenge was built; it is likely that the inhabitants were actively involved in building the monument in one way or another.
Wanting to find out more about this community, a team of archaeologists, led by members from the University of Cambridge, analyzed nineteen coprolites found at the site. This analysis revealed that five of them -- one human and four from dogs -- contained the eggs of parasitic worms. This marks the earliest evidence of intestinal parasites ever found in the UK for which the species that produced the feces is also known.
"The type of parasites we find are compatible with previous evidence for winter feasting on animals during the building of Stonehenge," according to Dr Mitchell.
The eggs identified in these coprolites belong to the capillariid worm family and were identified from their distinctive lemon-like shape. These parasites are quite well-spread around the world and are able to infect a wide range of animals. There are precious few examples of a species in this genus infecting humans in Europe, the team explains, and when that does happen, the eggs become lodged in the liver and do not pass in the stool.
Therefore, the discovery of these eggs in human feces points to the individual eating raw or undercooked internal organs from an already-infected animal -- most notably the lungs or liver. This way, the eggs passed straight through their digestive tract, ending up in the feces. The coprolites were determined to have been produced by humans or dogs based on an analysis of sterol and bile acid content at the National Environment Isotope Facility at the University of Bristol.
Alongside the coprolites, excavations of the middens (refuse heaps) at Durrington Walls also produced fragments of pottery and stone tools and an impressive haul of 38,000 animal bones. The overwhelming majority of these -- 90% -- were pig bones, with cow bones making up just shy of the remainin 10%.
"As capillariid worms can infect cattle and other ruminants, it seems that cows may have been the most likely source of the parasite eggs," said Mitchell. "Finding the eggs of capillariid worms in both human and dog coprolites indicates that the people had been eating the internal organs of infected animals, and also fed the leftovers to their dogs," adds co-author Evilena Anastasiou, who assisted with the research while at Cambridge.
Previous research on cow teeth recovered at the site suggests that cattle were being herded to Durrington Walls from Devon or Wales -- a trek almost 100km in length -- for large feasts. Based on butchering marks found on the bones here, beef was mainly chopped in stews. Bones were also broken to extract the marrow they contained for consumption.
One of the coprolites -- produced by a dog -- stood out as it was contaminated with the eggs of a species of fish tapeworm, which can be contracted by eating raw freshwater fish. Since no evidence of fish consumption at the site was forthcoming, the team is confident that the dog arrived at the site already infected with the parasite.
"Isotopic studies of cow bones at the site suggest they came from regions across southern Britain, which was likely also true of the people who lived and worked there," said Dr Mitchell.
The dates for the occupation of Durrington Walls match the time when phase two of the construction of Stonehenge was underway. This is the time when the trilithons, the two vertical stones supporting the third, horizontal ones, were set in place. The seasonal nature of habitation of Durrington Walls, together with the evidence of wide-scale feasting at the site in the form of pottery and animal bones, suggest that people came to overwinter here at least in part in order to work on Stonehenge. Meanwhile, there is almost no evidence of habitation or feasting near the monument itself.
The paper "Intestinal parasites in the Neolithic population who built Stonehenge (Durrington Walls, 2500 BCE)" has been published in the journal Parasitology.