Smelling a Rat on Easter Island

Tonight I attended a talk by Terry Hunt, an archeologist whose done a lot of research on Easter Island. Let me preface this by noting that I’ve been interested in Easter Island since watching an episode of “In Search Of” back in the late 70’s. My curiosity was further piqued by the historical fiction film about the island called Rapa Nui. Jared Diamond also used it to help illustrate his ideas in his book Collapse.

However, tonight’s talk was a great example of how the constant review and revision process of science can lead us to better understandings through maintaining a critical approach to ‘established’ realities. The big ideas behind the ‘collapse’ of Easter Island (that supposedly left a society of people who built the great stone statues) are that they deforested, overfished, and drastically degraded the ecology of the island due to self-aggrandizing competition between zealous leaders of these people. The iconic statues were a product of elite pride which drove the populous to carve these giants to serve their chieftain.

The narrative that Dr. Hunt wove from his years of research on the island turned out to be quite different. Strangely, at the beginning of his research, he truly believed he was merely going to catalog the evidence that was going to support the assumptions of previous researchers who had proposed the human driven ecological collapse. A different picture began to emerge.

One of the first things that got dealt with was the movement of those giant statues. Originally, when Europeans first landed on the island, they had asked the inhabitants how the monuments had been moved from the stone quarry to their standing sites, which can be up to several miles away. The native residents said in essence ‘They walked there’. This answer was considered a humorous ruse by the early Europeans, and it was dismissed and left a mystery. Through a closer analysis, as well as some collaboration with a design program in Washington, they came to discover that the statues could be easily moved by a simple process of rocking them right to left. The way that the statues were constructed gave them the perfect center of gravity for just such movement. The reason that this discovery is important is because it meant that deforestation wasn’t truly necessary to construct any kind of sled or rollers in order to transport the statues. The natives had not lied. The statues had indeed walked there (with a little help from the islanders, of course).

So what made the trees disappear? Were they making a bunch of boats for fishing? The answer is no. The species of palm that covered the island when the Polynesians first colonized it were soft and fibrous on the inside with a very thin bark, which made them terrible material for dugout canoes. This situation, coupled with the fact that the nearest island was over a thousand miles away, essentially left them stranded. However, there were some stow aways that arrived on the island with them, the pacific rat.

This rat is different from its old world cousins in that it isn’t really a disease vector. Instead, it is a natural deforester AND a fast growing source of protein. Like other rats, they are prolific breeders. To illustrate this, Dr. Hunt presented the figure that the amount of time it takes to go from one breeding pair of rats to 1 million in an environment with no predators only takes a couple of years because the number of rats doubles every 47 days. 47 days! The rats feed on the yummy seeds and fruit dropped by the palms. So within a couple of years of the Polynesians making landfall at Rapa Nui (Easter Island), the process of renewal in this palm jungle was brought to a screeching halt. The abundance of rat bones in the soil layers that date to this period support this notion.

The early Polynesians who were colonizing the island probably didn’t mind. They were agriculturalists who preferred a clearing of the palms to make way for the planting of taro and yams, the main subsistence crops of many pacific island cultures. Once the trees were gone, though, there was nothing holding back the wind that swept over the island, and that wind carried salt spray onto the island’s soils making them unfit for cultivation. When the Europeans made landfall, the island looked rocky and forbidding, and from the European agricultural perspective, it looked unfit to grow crops.

This was the prevailing idea until Terry and his research uncovered a peculiar pattern. At numerous places across the island, it seemed as if rocks had been collected and concentrated in patches. As they looked into the patterns and began testing the conditions that these rock fields created, they came to find that these were actually cultivation plots. The subsurface conditions of these rocky fields were far more stable and nurturing to these cultivars than the soils.

The dispersal of these fields was fairly even, and it suggests that small bands merely tended their own plots. What this also implies on a social level is that they were more likely to be an island of friendly neighbors. Considering that the entire island gets to experience boom or drought together, there was little need for conflict. The experience of resource scarcity or abundance was island-wide rather than patch or range based like on larger land masses.

Because of the scarcity of resources on the island, there was a need to control the population. This usually meant maintaining the number of births either through birth control or infanticide. This is a common theme for island cultures. Limited land means limited resources. Too many mouths to feed leads to starvation. However, the creative energy and social satisfaction in a community that comes with having children regularly is missing. Dr. Hunt proposes that the creation of the idols was a way for people to gather, create and foster solidarity in a community where children are scarce by neccesity. The creation of the famous statues was a mechanism to keep peoples’ morale up.

So the 3000 or so residents, who greeted the first Europeans to arrive, were not the remnants of a once great people but rather living how people had been living for hundreds of years since colonizing the island originally. The real devastation came with the diseases from first contact with Europeans. This revised tale of Rapa Nui helps support the notion that the tools of improvisation (making do with what’s at hand, holding the frame of ‘we all win or lose together’, group collaboration being an avenue to fulfillment) really are the most apt approach for dealing with adversity and creating populations of people with a core mindset of sustainability. Easter Island is no longer an example of the dangers of overconsumption, but a testament to the tenacity, ingenuity and wisdom people can bring to potentially desperate situations.

Terry Hunt’s book about this subject comes out this June. Check it out.