Complex structure made by African herders unusual for a mobile population
Roughly 5,300 years ago, a group of sheep herders in East Africa began an extraordinary effort to care for their dead.
It was a time of great upheaval in their homeland. Global climate changes had weakened the African monsoon system, causing a significant drop in rainfall. The herding of livestock spread south from Sahara. What is now known as Lake Turkana in northern Kenya shrank by half over the succeeding centuries.
These early herders dug through about 1,000 square feet of beach sand down to bedrock and gouged out pits. They buried their dead there: the bodies of men, women and children of all ages, many with personal items and ornamentation.
When the crevices they had dug into the bedrock filled up, the herders piled bodies on top of the pits, carefully placing large rocks over the head and torso of each corpse. They did this for about 700 years, burying at least 580 people and perhaps 1,000 in all, according to a study published this month in the Proceedings of the National Academy of Sciences.
Then, for reasons scientists don't understand, at about the same time that Lake Turkana stopped shrinking, the people decided to stop burying their dead this way. The pit area wasn't yet full. But the herders covered it over with pebbles and then, to mark the spot, somehow managed to drag a dozen giant basalt pillars to the site from almost a mile away.
“Once the landscape was stabilized, perhaps these social anchors became less important,” said Elisabeth Hildebrand, the paper’s lead author and an associate professor at Stony Brook University in New York.
The place, now called the Lothagam North Pillar Site, was never used as a burial site again, and lay virtually undisturbed until an international team of researchers, led by Dr. Hildebrand and Katherine Grillo, an assistant professor at the University of Florida, Gainesville, began to examine it.
There are five other sites around the lake with similar pillar markings, and previous research by another group suggests that at least one of them was also used as a monumental cemetery.
The new paper covers the results of digging deep into and at the fringes of the site during the summers of 2012, 2013 and 2014. The researchers also used ground-penetrating radar surveys to examine its dimensions.
“From start to finish, over a period of what was at least several centuries, people were demonstrating a high degree of intentionality and planning and careful implementation of this idea that everybody should be buried together in this singular location,” Dr. Hildebrand said.
This idea turns on its head the long standing notion that they become organized enough to build complex structures like cemeteries, said Susan McIntosh, a professor of anthropology at Rice University in Houston, who was not involved in the research.
“In archaeology, we used to think we understood that monumental constructions were associated with sedentism and food and/or labor surpluses commandeered by elites,” Dr. McIntosh said. “This was part of mainstream narratives about the ‘rise of civilization.’”
But? excavations of sites like Lothagam North, Gobekli Tepe in Turkey and Poverty Point in Louisiana show that ancient mobile populations could also build monumental works, Dr. McIntosh said.
The burial site also indicated the lack of an apparent hierarchy.
“This truly was a place that accommodated all ages and life stages,” Dr. Hildebrand said. “It wasn't reserved for a chosen few or people of special high status. Everybody was accommodated there.”
Most were buried with ornamentation, including an infant who wore an ostrich eggshell bracelet. One man was buried with a headdress decorated with what researchers figure out were 400 carefully arranged gerbil teeth. He probably wore the headdress during life.
Gerbils, Dr. Hildebrand noted, are not generally associated with power or strength.
“On the one hand, they’re building this vast communal cemetery that required a ton of labor to create for several centuries,” she said. “On the other hand, they’ve got this crazy personal idea of style, where everybody decorates themselves in their own personal, eclectic way.”
Digging up these remains wasn't easy. Lake Turkana is very remote today, as it likely was in ancient times, Dr. Grillo said.
It's also extremely sunny and windy, making excavations of fragile bones quite tricky, said Susan Pfeiffer, an emeritus professor at the University of Toronto, who serves as the team’s senior bioarchaeologist. The bones disintegrated when exposed to bright sunlight, and the windy conditions made it tricky to keep the dig area shaded, she said.
Dr. Hildebrand is now concerned about the future of the pillar sites. She and others on the team have been working with local residents, as well as the Kenyan national museum, to preserve Lothagam North.
“Before, the site was naturally protected from human threats by its own distance,” she said. “Now, many more people have motorbikes.”
Dr. Hildebrand said she remains impressed that these ancient Lake Turkana people reacted to the stress of so much simultaneous change by collaborating rather than fighting － a lesson, she says, that has resonance in our own time.
“These are people who responded to very difficult and what must have been both strategically and emotionally challenging conditions with exceptional creativity and community spirit,” she said. For today, “it's important as all these changes are taking place around us to retain our sense of community.”
