Guide to the Culture and Ecology of Easter Island

What has science learned about the people who settled Easter Island?

One and Fifteen Moai, Easter Island
One and Fifteen Moai, Easter Island. Phil Whitehouse

Easter Island, home of the enormous statues called moai, is a tiny dot of volcanic matter in the South Pacific Ocean. Called by Chileans the Isla de Pascua, Easter Island is known as Rapa Nui (sometimes spelled Rapanui) or Te pito o te henua by its inhabitants, who today are primarily newcomers from Chile and the Polynesian islands.

Rapa Nui is one of the most isolated, continuously inhabited islands in the world, lying some 2,000 kilometers (1,200 miles) east of its nearest neighbor, Pitcairn Island, and 3,700 km (2,300 mi) west of the nearest mainland and owner, central Chile. The roughly triangular-shaped island has an area of about 164 square kilometers (about 63 square miles), and it has three main extinct volcanoes, one in each corner of the triangle; the highest volcano reaches a maximum elevation of about ~500 meters (1,640 feet).

There are no permanent streams on Rapa Nui, but two of the volcanic craters hold lakes and the third contains a fen. Pools in extinct lava tubes and brackish water springs are located along the coast. The island is currently 90% covered by grasslands, with a few tree plantations: that was not always the case.

Archaeological Features

The most famous aspect of Easter Island are, of course, the moai: over 1,000 giant statues carved out of volcanic basalt and placed into ceremonial settings around the island.

The moai are not the only archaeological feature on the island that has attracted the interest of scholars. A handful of Rapanui houses are shaped like canoes. Canoe-shaped houses (called hare paenga) are often found just beyond and overlooking moai groups. According to historic records cited in Hamilton, some of them were 9 m (30 ft) long and 1.6 m (5.2 ft) high, and they were thatch-roofed.

The entrance gaps to these houses were less than 50 cm wide and would have required people to crawl to get inside them. Many of them had small carved stone statues which acted as household gods. Hamilton suggests hare paenga were conceptually and physically ancestral houses because they were built and rebuilt. They may well have places were leaders of the community met, or where elite individuals lived.

Other original Rapanui features include earthen cooking ovens with stone surrounds (called umu), rock gardens and walled enclosures (manavai); chicken houses (hare moai); quarries, roads built to move moai from the quarries about the island; and petroglyphs.

Easter Island Economy

Genetic research has shown that Rapanui was originally settled by about 40 Polynesians, circum-Pacific navigators likely originating from one of the islands in the Marquesas, perhaps Mangareva. They arrived about 1200 AD and lived undisturbed by contact from the outside world for several centuries. The original Easter Islanders probably relied on the large variety of birds that made the island, covered at the time with a lush palm tree forest, their home.

By AD 1300, horticulture was being practiced on the island, evidenced by the remains of house gardens, horticultural fields, and chicken houses. Crops were tended or grown in a mixed-crop, dryland production systems, growing sweet potatoes, bottle gourds, sugar cane, taro, and bananas. "Lithic mulch" was used to increase soil fertility; rock walls and stone circle planting pits helped protect the crops from wind and rain erosion as the deforestation cycle continued.

Rock gardens (called boulder gardens, veneer surfaces and lithic mulch in the literature) were used beginning in AD 1400, with the most intensive use at the time of the highest population, ca AD 1550-1650 (Ladefoged). These were plots of land which were built of basalt rocks: large ones measuring between 40-80 centimeters (16-32 inches) are stacked as windbreaks, others measuring only 5-0 cm (2-4 in) in diameter were deliberately mixed into the soil at depths of 30-50 cm (12-20 in). Rock gardens are used worldwide, to minimize fluctuations in ground temperature, reduce evaporation, prevent weed growth, protect soil from wind, and facilitate greater rainfall conservation. On Easter Island, the rock gardens enhanced growing conditions for tuber crops like taro, yams and sweet potato.

Recent stable isotope research on human teeth from burials dated throughout the entire habitation of the island (Commendador and colleagues) indicates that terrestrial sources (rats, chickens, and plants) were the primary source of food throughout the occupation, with marine sources becoming an important part of diets only after 1600 AD.

Recent Archaeological Research

Ongoing archaeological research about Easter Island concerns the reasons for the environmental degradation and the end of the society about 1500 AD. One study argues that a colonization of the island by the Pacific rat (Rattus exulans) may have exacerbated the end of the palm trees; another says that climatic changes had an effect on the agricultural stability of the economy.

The precise manner in which the moai were transported across the island-dragged horizontally or walked upright-has also been debated. Both methods have been tried experimentally and were successful in erecting moai.

The Rapa Nui Landscapes of Construction Project at University College at London's Institute of Archaeology is working with the residents to investigate and conserve their past. A three dimensional visual model of an Easter Island statue on display at the British Museum has been created by the Archaeological Computing Research Group at the University of Southampton. The image highlights the detailed carvings on the body of the moai. (Miles et al).

Most interestingly, two studies (Malaspinas et al and Moreno-Mayar et al) describe DNA results from studies of human interments on Rapa Nui and the state of Minas Gerais, Brazil that suggest that there was precolumbian contact between South America and Rapa Nui.