I have been pleasantly surprised by the great many documentaries aired on the BBC Four channel that focus on archaeology, perhaps none more so than a recent series entitled Lost Kingdoms of South America. Presented by the knowledgeable and engaging Dr Jago Cooper, the series explored various (and to me some unknown) cultures in the pre-Colombian continent. I admit to having a great interest in Mesoamerican and South American archaeology, as such it was a delight to watch these detailed documentaries.
Therefore I was quite happy to come across another BBC 4 feature the other day, this time with a focus on Easter Island (here-after Rapa Nui), a tiny Pacific volcanic island well-known for the megalithic human moai statues that dominate the landscape and the birdman cult that super-ceded the creation of the statues (Lipo et al 2013). For a previous undergraduate essay I had researched the island’s history so I was familiar with the ecocide theory, the tale of the island’s supposed descent into war/ruin after using up the majority of the island’s natural resources. However this documentary discovered a far more nuanced tale to tell.
Once again presented by Dr Jago Cooper, an archaeologist and curator at the British Museum, the 90 minute documentary was an interesting and informative show. It was a pretty comprehensive overview of the history of the people of Rapa Nui, discussing their somewhat still mysterious origins (Chapman 1997) right through to the issues that dominate the island to this day. It was also a show that actively engaged with a wide range of current specialists on the history and archaeology of the island. It detailed not just the controversial theories of the island’s ecological diversity decline, but also the range and depth of archaeological research conducted on an island that has captivated and captured the hearts of many.
I am not going to review the whole program here but I do want to highlight a few parts where, for me, the program really came alive with the great value that archaeology has to offer.
Ecology and Landscape at Rapa Nui
The ecology and landscape environment of Rapa Nui have undergone extensive changes throughout the human habitation of the island, perhaps none more so than in the last 400 years. Visitors to the island today will note the largely steppe like appearance of the landscape – the only trees still standing can largely be found around the main settlement of Hanga Roa in the south-west of the island. The island was previously heavily forested with trees, shrubs and ferns. The main predominate tree of the forested island was the now extinct palm tree Paschalococos disperta (Rapa Nui palm), which disappeared from the environmental record around 1650. It is important to note that while there are various extinction events of various flora and fauna (land-birds such as herons and parrots) throughout the island’s natural history, there seems to be a fairly major change in landscape and ecology in the middle of the 2nd millennium AD (Chapman 1997).
Although there are many theories on the collapse of the ecology of the island (from over-population, the various causes of intense deforestation and the impact of invasive species) it is likely thought that a combination of these and other factors were involved. It is not my intent here to discuss this but to highlight the implications of this in the archaeological record.
The loss of the forests that covered Rapa Nui has led to some serious consequences in the landscapes ability to hold minerals and water in the soil. The Roggeveen expedition of 1722, at least a century after the extinction of the main palm trees, stated that Rapa Nui was exceptionally fertile in its soil quality, that the population successfully cultivated sweet potatoes, bananas and sugar cane. Further expeditions in the 18th century repeated claims of fairly well fed individuals. This is interesting as we have archaeological and palaeoenvironmental evidence of a decrease in the ecological flora typically ascribed to a sub-tropical Polynesian environment.
The program shed light on this topic in a few surprising ways. Firstly there are numerous caverns throughout Rapa Nui, some of which have carved artwork and glyphs attributed to different tribal groups. Some, however, were clearly used as agricultural areas to help grow banana crops and sweet potatoes. Further to this there was also evidence of lithic mulch across the island, that at least some of the forest chopped down was to make way for agricultural plots of land. This, for me, was a new term I had not come across before. It is the laying stones (of varying sizes, but in this case just under football size) across the landscape in small plots of lithic mulch gardens or in larger areas to encourage more nutrients into the soils and stabilize the landscape.
This encourages the retention of minerals and water in the soil below encouraging plant growth and helps to increase the crop biomass and overall yields. The stones also help to decrease/stop the rate of soil erosion from wind or water run off and shadow the soils from direct sunlight whilst also producing an environment which encourages other vegetation to grow (Lightfoot & Eddy 1994: 425). Lithic mulch gardens have been noted at a variety of archaeological sites across the world that occur in predominately dry environments (Anasazi and Hohokam sites in Arizona, Negev in Israel, Maori in New Zealand etc) (Lightfoot & Eddy 1994: 426).
Inevitably the ecology and landscape has changed due to the actions of the human populations, both from those that are aboriginal and those that visited the island post-European contact. Perhaps most damaging to the island soil ecology was the widespread grazing of over 70,000 sheep in the early 20th century, helping to destabilize the soils which has led to intense soil and field erosion ever since.
The Moai and the Ahu Platforms
The moai are the quite wonderful sculpted megalithic stone statues, made mostly of volcanic tuff, that dominate the island. They are largely found on either ahu platforms in groups or dotted around inland individually (termed road statues). They are largely quarried from the main site of Rano Raraku on the foothills of the Terevaka volcano, the highest point on the island. Around 887 statues have been documented and recorded so far, with almost 50% of them still located in and around Rano Raraku in a variety of completed states (Lipo et al 2013). The statues were created over a 500-600 year period in the early part of the 2nd millennium AD, although exact dates are not known.
The smoothed statues are known for their overly large heads and minimal stylistic appearance that are carved in flat planes. With an average height of 4 meters and width of 1.6 meters, the statues weigh in at 12 tonnes on average, although there are exceptions and some are often rather larger and heavier. Some statues also have pukao, either hats or hairstyles, that adorn the top of the statue heads, which can weigh many tons themselves. Although nearly every statue recorded is in a standing pose there is one statue that shows a kneeling position, Tukuturi at Rano Raraku, that also has a beard – a highly unusual feature of the statues and reminiscent of other Polynesian societies. It is thought that this individual was carved late in the statue phase.
A number of the statues are found on the ahu fitted stone ceremonial platforms that can be found around the whole perimeter of the island. Nearly every ahu platform faces inland – there is only one documented case where the statues face out towards the sea. It is thought that the statues represent the chiefs of ancestors of the aboriginal population, with the individuals facing inland towards their respective tribal land (Lipo et al 2013). Researchers have also noted the boundary motifs of tribes on some moai throughout the Rapa Nui island, suggesting that fairly individual identities existed (Chapman 1997), regardless of their ancestral origin (Stefan 1999). The ahu platforms consist of carefully fitted stone sections with distinct stone wings to the side of the platform and stone fields out to the front of the platform.
The documentary highlighted the fact that it is likely a variety of methods were used to transport the statues to their respective sites. There was a pretty impressive part where it was highlighted that the statues could walk to site:
Lipo et al. (2013) have stated that wear marks on the torso and heads of the statues indicate that great pressures were hinged at these areas suggesting that the size, shape and centre of gravity of the statues all point towards a rocking motion to gather the momentum to walk the statues.
After the initial contact with European sailors following Roggeveen’s landing in 1722 (in which the moai were still standing) it was reported that the toppling of the statues had commenced, with almost no statues standing on the ahu platforms by 1868. It has been postulated by some researchers and historians (Lipo et al. 2013) that the statues were thrown down with force by rival tribal bands, but others have pointed out that at least some of the statues were carefully placed face down. What is known is that some of the ahu platforms where the statues are face-down also function as ossuaries or burial complexes. Today a total of 50 moai have been placed back in the standing position, whilst a few have been shipped to institutions are the world (Lipo et al. 2013).
For further information on the Moai I’d recommend checking out an ongoing project entitled Easter Island Statue Project, co-directed by Jo Anne Van Tilburg and Cristián Arévalo Pakarati, whose homepage can be found here. A detailed map of the moai on the ahu platforms on the island can be found here.
Human Osteology and Population Origin
I think it is pertinent to touch on here a few of the (few) human osteology studies that have been carried out on aboriginal skeletal material of the Rapa Nui. It has long been argued by some early archaeologist, such as Thor Heyerdahl, that Rapi Nui and other Polynesian islands were settled by Native Americans. Although some archaeologists concede that contact between Native Americans and Polynesians was feasible (Chapman 1997: 161), the majority of the osteological and genetic tests carried out on human skeletal material indicates a Polynesian origin for the aboriginal inhabitants of Rapa Nui (Chapman 1997, Chapman & Gill 1998, Stefan 1999).
Chapman & Gill (1998: 189) measured the stature of 92 individuals from the Rapa Nui aboriginal population (54 males and 38 females from prehistoric (A.D. 1680-1722) and protohistoric (A.D. 1722-1868) populations. The individuals were taken from the various tribal populations on the island and the bones (in ranked order: femur, tibia, fibula, humerus, radius or ulna) were measured and analysed using a regression formula devised for New Zealand Maori populations (Chapman & Gill 1998: 189). The results stated that there was no statistical difference between the tribal areas of the island and stature, male average was 1726 mm and 1595 mm for females, reflective of general sex dimorphism (Chapman & Gill 1998: 191). The stature range was found to be within range of other Polynesian groups and there were no obvious differences in stature within the population of the Rapa Nui island.
Stefan (1999) and Chapman’s (1997) studies both indicate that the initial aboriginal population of Rapa Nui were from Polynesian origins. Stefan’s (1999) studied 50 cranio-facial measurements on the crania of prehistoric/protohistoric Rapa Nui populations and discovered greater between-group homogeneity in males than females but not the population as a whole. Chapman (1997: 171) study does highlight the need to thoroughly investigate the prehistoric and protohistoric populations genetically for any further population admixture and genetic drift from later populations, with the need to specifically sample individuals from each main geographic location of the island. As far as I am aware I do not know of any stable isotopic work that has been carried out on the skeletal remains, but this could add another informative dimension to understanding the Rapa Nui culture (1).
It must also be remembered the island was repeatedly visited (and raided) after Roggeveen’s first landing by European ships in the same century, which ultimately led to a rejection of all ships by the Rapa Nui. During the 19th century Peruvian ships also repeatedly and successfully made slave raids on the island, capturing up to a thousand aboriginals to work in the mines in Peru. The slave raids, but also the introduction of new diseases from the Europeans and from surviving miners, caused the aboriginal population to dramatically fall resulting in an aboriginal population of only 111 individuals at one point in 1877. Although a historic low, the population had undergone fluctuation before but probably never to this dramatic extent. The documentary state that around half of the modern population (around 2500 individuals) claim to be genetically related to the original aboriginal population.
The program also produced a succinct point by highlighting the ongoing struggles of Rapa Nui to become recognised as an independent island. There are still many controversies surrounding the Rapa Nui culture and as highlighted above there is still little agreement on certain key points of the population history of the island and the ecological effects that this produced.
Although only briefly mentioned here it is worth noting that Rapa Nui has evidence for a rich and diverse culture. Interestingly Forment et al. (2001) highlight the fact that the wooden carvings of human figures, known as moai kavakava, were being carved and produced in the same period as the terminal phase of the megalithic statues. Also noted is the fact that the wooden carvings probably do not indicate accurate physical reflections of the population (Forment et al. 2001: 532) as some researchers have suggested. There are also numerous petroglyphs present throughout the island as well as an apparent script called rongorongo, which included glyphs of geometric and pictographic images (Chapman 1997). Although Rapa Nui is only 15 miles by 7 miles in size, it has produced an incredibly diverse cultural legacy and material culture. This is echoed today by the living population who understand the very real threat of population collapse and remain intent to keep their culture, and cultural heritage, alive.
(1). If I am mistaken (I only did a quick literature search) please email me or drop a comment below.
Important Update 25/10/14
New genomic evidence has shown that the human population of Rapa Nui had contact with the Native American populations from around AD 1300-1500. The genome wide study of 27 native Rapa Nui individuals has discovered that there was significant contact between the inhabitants of Rapa Nui and Native American populations from around 19 to 23 generations ago. The evidence for European based population admixture dates from around AD 1850-1895. This is an outstanding piece of news, please see the Past Horizons article for more information. The 2014 Current Biology article can be found here.
- Watch the documentary Easter Island: Mysteries of a Lost Word (UK BBC Iplayer only, available until the 11th of February).
- Explore the website of the Easter Island Statue Project.
- Watch a Moai walk here!
Chapman, P. M. 1997. A Biological Review of the Prehistoric Rapanui. The Journal of the Polynesian Society. 106 (2): 161-174. (Open access).
Chapman, P. M. & Gill, W. G. 1998. Estimation of Stature for the Prehistoric/Protohistoric Rapanui. The Journal of the Polynesian Society. 107 (2): 187-194. (Open access).
Forment, F., Huyge, D. & Valladas, H. 2001. AMS 14C Age Determinations of Rapanui (Easter Island) Wood Sculpture: Moai Kavakava ET 48.63 from Brussels. Antiquity. 75: 529-32. (Open access via academia).
Lightfoot, D.R. & Eddy, F.W. 1994. The Agricultural Utility of Lithic-Mulch Gardens: Past and Present. GeoJournal. 34 (4): 425-437. (Partially open access).
Lipo, C. P., Hunt, T. L. & Haoa, S. R. 2013. The ‘Walking’ Megalithic Statues (Moai) of Easter Island. Journal of Archaeological Science. 40 (6): 2859-2866. (Abstract only).
Stefan, V. H. 1999. Craniometric Variation and Homogeneity in Prehistoric/Protohistoric Rapa Nui (Easter Island) Regional Populations. American Journal of Physical Anthropology. 110 (4): 407-419. (Abstract only).