RENEE MONTAGNE, HOST:
Before King Tut, even before the ancient Egyptians began carefully preserving some of their dead, in fact a couple of thousand years earlier, a much simpler society made the first known mummies.
NPR's Elizabeth Shogren reports on the somewhat gruesome reason this practice might have developed.
ELIZABETH SHOGREN, BYLINE: The first mummy makers lived about 7,000 years ago, in South America. They were on the coast near the border between modern day Peru and Chile. They're called the Chinchorros.
Chilean ecologist Pablo Marquet studies them and the extremely dry desert where they lived. It was so dry in fact that dead people turned into mummies, naturally.
PABLO MARQUET: Once you die, you stay around. Because you don't visually disappear because of the decomposition that happens in many other environments.
SHOGREN: At some point, the Chinchorro stopped leaving it all to nature. They started mummifying their dead. And they started dressing them up with wigs, clay and paint. But why?
A few years ago, Marquet got together with archeologists and paleoanthropologists to answer that central question. Here's what they knew. The early Chinchorro were hunter gatherers. They did bury their dead but in shallow graves only about a foot or two from the surface. It only took a little erosion for these dead people to be revealed.
MARQUET: Most other populations, the dead disappear and become recycled back into the system. But here they stay around.
SHOGREN: The living also encountered the dead when they dug new graves. And they dug a lot of graves because diseases and arsenic poisoning from drinking water were rampant. This adds up to a lot of corpses on the landscape. In fact, Marquet and his team calculated that the average person would encounter these natural mummies, at least hundreds of times in their life time, and perhaps a lot more frequently.
MARQUET: Wow, I mean the question was why they started to mummify their dead. And I think the key insight came from the observation of their environment.
SHOGREN: Marquet thinks seeing all these mummies inspired the Chinchorros' death rituals. Marquet's team also looked data about the climate thousands of years ago.
MARQUET: We started seeing the data and everything was like aligning perfectly. I mean we couldn't believe it. I mean I said wow, this is really interesting.
SHOGREN: It looks like, the Chinchorro started preserving and decorating corpses during a time when their climate was wetter. There was more water and more seafood around to support a bigger population. Artifacts from that era confirm that the population surged around this time.
MARQUET: Because if you have more individuals in a population, and they start interacting, it is more likely that new ideas will emerge. And once new ideas emerge, they will spread faster.
SHOGREN: The idea is, the more hospitable environment gave people more free time They no longer needed all their time for hunting and gathering. They had time to care for their dead and to pass on their embalming techniques to others.
The findings appear in the journal Proceedings of the National Academy of Sciences. These mummies haven't revealed all their secrets yet. Researchers are still trying to explain why infants and fetuses were the first South American mummies. Other cultures reserved this treatment for their elite.
Elizabeth Shogren. NPR News.