Mystery of Rapa Nui: What really happened at Easter Island?

The Rapa Nui people, who have lived on Easter Island since before Europeans arrived, accomplished incredible feats of engineering. But some centuries ago, their numbers dwindled. What kickstarted the collapse of this civilization?

Easter Island is famous for its humongous stone statues, called moai. But the island itself is tiny. The land takes up just over 63 square miles in the South Pacific Ocean, some 2,300 miles west of Chile. 

But for such a small portion of the globe, the island has captured a lot of attention.

The moai aren't the only alluring aspect of Easter Island. It's the mysterious demise of a clever civilization that once flourished on the tiny island that has generated prize-winning books, films, and competing scientific investigations.

And that's where our story begins.

Centuries ago, the ancient civilization on Rapa Nui, the traditional name of Easter Island, was thriving. They were skilled farmers, employing careful agricultural techniques to feed large populations. They also carved the humongous, heavy moai and engineered a way to move the gigantic stone statues around the island. But somehow, the population shrunk. This downfall occurred around the time Europeans first encountered the tiny island.

So what happened? There are a few things that scientists and historians agree on about the Rapa Nui civilization, but some of the tales are starkly different. Two explanations are particularly opposed.

The traditional explanation, detailed in Paul Bahn and John Flenley's book "Easter Island, Earth Island" and later popularized by Jared Diamond's book "Collapse," describes an overzealous population committing what Diamond dubs "ecocide," or eco-suicide. That story goes something like this:

Before the first millennium AD, a sea-faring population from Polynesia ended up on the then-uninhabited island. The inventive group began thriving and multiplying. As they multiplied, they cut down more and more trees to make space for crops and used more and more of the natural resources. 

But the tiny island couldn't support such an unfettered population. "They did terrible damage to their environment," Dr. Bahn tells The Christian Science Monitor. "They adapted to what they'd done as well as they could, but nevertheless, they had done tremendous damage to their environment."

This is what Diamond described as ecocide. As resources grew thin, the once flourishing civilization began to struggle. And that desperation led to conflict, as the people fought to survive. Warfare broke out. By the time Dutch explorer Jacob Roggeveen spotted Rapa Nui (and dubbed it Easter Island for the day he arrived) in 1722, the population was a ghost of its earlier days.

Hints of this traditional story run through the accounts of other European explorers who came to Rapa Nui. For example, Captain James Cook wrote upon visiting Easter Island in 1786 that he "had no doubt that this peo[ple] were indebted to the imprudence of their ancestors for their present."

But two archeologists, Carl Lipo and Terry Hunt, are telling a story that lays blame elsewhere.

Their explanation stands in stark contrast to the traditional story, starting with the very timing of the original inhabitants' arrival on the island. While Bahn and Dr. Flenley suggest that humans were living on the island before the first millennium of the common era was over, Dr. Lipo and Dr. Hunt say people didn't arrive until around 1200 AD.

According to Lipo and Hunt, the Rapa Nui people went on to thrive, although not in as large numbers as the traditional story suggests. And their agricultural lifestyle wasn't their ruin. Instead of committing ecocide, the Rapa Nui were still doing well when the Europeans arrived. 

What ultimately did in the thriving civilization, they argue, was contact with Europeans. The explorers carried diseases, thinning the population, before ultimately enslaving and decimating many.

Lipo and Hunt have been taking the traditional story to task, re-examining the evidence to propose their explanation. One lingering question for the team was the issue of massive warfare.

Weapons or gardening tools?

As the traditional story tells it, tribes on the tiny island were viciously fighting over dwindling resources. In what seemed like support for that explanation, somewhat arrow-shaped obsidian chunks were found scattered across fields on the island, predating the Europeans. 

So if they weren't the remnants of bloodshed, what were these glassy shards?

Called mata'a, the obsidian objects were clearly used for something. "They're vaguely triangular with a stem on them," Lipo describes. 

"Europeans early on described them as having these triangular, glassy objects on a stick," he tells the Monitor. "They call them spears, but, of course the Europeans call anything on a stick a spear because they had spears and they look like spears in general."

But in a new study, Lipo and Hunt re-examined the mata'a and suggest they were just gardening tools, not weapons of mass warfare. That paper was published Tuesday in the journal Antiquity.

Lipo says the mata'a couldn't have been weapons of mass, lethal warfare because they wouldn't have been very effective at killing people. If they were thinner and particularly pointy, he says, it would be a different scenario. Instead, "they're thick, they're randomly shaped, basically they're sharp edges on sticks," he says.

"When we start to look at where they're found and the wear patterns we see on them, they're best explained as agricultural implements," Lipo says.

But, Bahn says, "Nobody has ever claimed that all of the mata'a were weapons." Instead, they were probably used for all sorts of things. "But they did use some of them as weapons."

He adds that the European explorers repeatedly described spears in the hands of the Rapa Nui. Bahn particularly highlights the description by Spanish explorers in 1770 of "people with terrible wounds."

Sure the mata'a weren't arrow-shaped or perfect stabbing weapons, but that might not matter, Bahn says. Attached to the end of a stick, the glassy objects could do some gruesome damage as a slashing weapon. And, he adds, that could describe the wounds spotted by the Spanish.

In these two explanations, Bahn says, "we're just circling around the same pieces of evidence." 

The historical context, not the evidence, might be the problem. Perhaps those European explorers' assumptions set the wrong stage, Mara Mulrooney, a Hawaiian anthropologist who also works on the island, suggested in an interview with NPR in 2013.

"Archaeologists, instead of looking at the evidence itself, were taking the evidence and putting it into this existing framework that was really outdated," she said at the time.

Dr. Mulrooney's own research suggests that the soil actually benefited from the deforestation that the traditional story says was the main downfall of the Rapa Nui people. 

Inherently violent or inherently peaceful?

At the root of both stories are two differing ideas about humanity. 

In the ecocide scenario, humans are innately violent. Sure the Rapa Nui people were excellent engineers, reaping many rewards from their environment over the centuries, but they were descendants of populations in Polynesia. And, Bahn says, ancient Polynesian societies were very violent.

Lipo suggests a different view, pointing out that there was much stronger evidence of warfare in Polynesia with forts and clear weapons dotting those ancient civilizations.

"Humans are amazingly social," he says. "Our success is dependent on clan groups, family groups, community groups and we work together incredibly well." It's that cooperation that would have been necessary to survive on the remote island of Rapa Nui.

So which scenario is it? Did the Rapa Nui people decimate their landscape, leading to desperate times and violent, desperate measures? Or were they doing fine until the Europeans arrived?

In other words, was it ecocide or genocide?

Perhaps new evidence will confirm one scenario down the road.

"No research is ever exhaustive," Bahn says. 

"Perhaps the story may change, perhaps the pendulum may swing back toward supporting a collapse," Mulrooney, whose research supports a story more in line with Lipo and Hunt's work, said. "But as of now, you know, I like to think that as scientists we trust what the data tell us."

"That’s the beauty of archaeology, is that it’s always changing," she said.