Archaeologists suggest that 7,000 years ago, a Chilean tribe began mummifying children after they died of natural arsenic poisoning.

Chinchorro mummies are seen inside the San Miguel de Azapa museum, outside Arica in northern Chile. The 7,000-year-old specimens are the oldest-known artificially preserved dead, dating thousands of years before Egyptian mummies.Ivan Alvarado / Reuters

Living in the harsh desert of northern Chile’s Pacific coast more than 7,000 years ago, the Chinchorro fishing tribe mysteriously began mummifying dead babies — removing internal organs, cleaning bones, stuffing and sewing up the skin, putting wigs and clay masks on them.

The Chinchorro mummies are the oldest-known artificially preserved dead, dating thousands of years before Egyptian mummies, and the life quest of the archaeologists who study them is to discover why this early society developed such a complex death ritual.

Archaeologist Bernardo Arriaza, who studies the Chinchorro at the University of Tarapaca in Chile’s northernmost city, Arica, launched a daring new theory this year.

“I was reading a Chilean newspaper that talked about pollution and it had a map of arsenic and lead pollution, and it said arsenic caused abortions. I jumped in my seat and said, ‘That’s it,’” Arriaza said.

Arriaza says high levels of arsenic in the water in the region, which persist to this day, meant more premature births, stillbirths, spontaneous abortions and higher infant mortality among the Chinchorro.

“We’ve always known that the Camarones (the area where the mummies are found) had a lot of arsenic, and the first mummies were children,” he said.

He posits the Chinchorro began preserving dead babies to express personal and community grief and later began mummifying adults as well, and the practice became more elaborate.

More than 100 tiny bodies

Since the 1960s, archaeologists have excavated more than 100 delicate, diminutive bodies, many preserved intentionally. They were stuffed with plants and sea grasses and decorated with clay. They have also found fishing hooks, baskets and sea shells used as pallets, still stained with the red and black paint used to decorate the mummies.

The Chinchorro were hunter-gatherers who lived at river mouths, fishing with spears, hooks and nets and building their movable shelters from sea-lion pelts and bones.

Their primitive life without domesticated animals, pottery, agriculture or metallurgy contrasts with the elaborate mummification they developed, thousands of years before the Inca civilization dominated this same area and also practiced mummification.

“These complex funerary practices are usually associated with more advanced societies with a state system, but here you are talking about hunter-gatherers who lived with a simple social and political organization,” said Arriaza’s colleague at the University of Tarapaca, archaeologist Vivien Standen.

The practice lasted more than 3,000 years and went through different stages before the Chinchorro society disappeared about 2000 B.C.

The earliest mummies were like statues covered with unbaked black clay.

Thousands of years later the treatment of the skin and bones became more elaborate and the Chinchorro began finishing their mummies with red ochre paint on open-mouthed masks.

Orders not to dig

The University of Tarapaca is struggling with scarce funds to preserve the dozens of mummies already dug up. There is no money to excavate new mummies, and nowhere to put them either.

“We have a research policy, and we order our academics not to dig. They have to do their research on the existing material,” said Hector Gonzalez, head of the university’s anthropology department, which runs a small museum at San Miguel de Azapa outside Arica.

The museum’s warehouse — off limits to the public — holds 42 of the anthropology department’s 130 mummies. But it’s a low-budget preservation effort of earthquake-proof carts and beds of sand holding the small bodies. There’s no money for controlling temperature or humidity to stem deterioration.

The museum has an operating budget of just $130,000 a year, but it recently received $750,000 from the university and the local government to build a new building that will house many of the Chinchorro mummies in a new exhibit so that visitors can finally view them.

Gonzalez said the new building is an important step but called on private enterprise to get involved and help the university properly store and excavate the remains of this unique ancient culture.

Mummies everywhere

Despite the no-excavation rule, mummies keep popping up around Arica, where a salty, dry climate has preserved burial grounds for millennia.

Digging for a hotel in downtown Arica earlier this year, construction workers came across a large cemetery. The hotel project was halted and the university agreed to purchase the land and turn it into an onsite museum to avoid moving the fragile mummies.

Standen, who has studied the Chinchorro for 20 years, is now investigating the quartz spearheads embedded in some of the mummies’ bones and evidence of blows to the left side of their faces, and developing a theory about possible ritual violence.

What she and Arriaza are sure about is that the mummified bodies became religious art — statues with a spiritual meaning — after the Chinchorro spent months preparing them.

“They lived with them a while, they probably took the mummies from place to place with them” before eventually placing them in simple collective tombs, Standen said.