Around 100,000 years ago humans left Africa, where they originated, and gradually spread north and east into Europe and Asia. Between 50,000 and 25,000 BCE, using simple rafts, people gradually dispersed through the large islands of South-East Asia. Eventually they reached Australia and New Guinea, which were then connected by land.
About 3,000 years ago people sailed south-east from the Solomon Islands further into the Pacific Ocean, and settled most of the islands of Melanesia. Between 1100 and 800 BCE they spread rapidly to Fiji and West Polynesia, including Tonga and Samoa.
The last Pacific migrations, between 1200 and 1300 CE, were to the distant points of Polynesia – Hawaii, Easter Island and New Zealand (1250–1300 CE). Evidence that they reached South America several centuries before Europeans did so is inconclusive.
While this sequence seems rather straightforward, the exact dates and the order of settlement are debated. Experts often disagree, and there are competing theories. The date for the arrival of people in New Zealand is no exception.
New Zealand was one of the last habitable land masses to be settled. Migrants sailed in double-hulled canoes from East Polynesia – the last major voyages in the exploration and settlement of the Pacific Islands.
Many methods have been used to determine the date when they first arrived, and when they settled. Although no single method is foolproof, all show remarkable agreement that permanent Polynesian settlement was established around 1300.
The method of genealogical dating involves counting back through the generations of Māori to the arrival of their ancestors in tribal canoes. In the early 2000s most tribal genealogies, or whakapapa, placed settlement at 24 to 27 generations ago. Assuming there are 25 years per generation, this gives a date of 1325–1400 CE.
Genealogies also include earlier ancestors. Many oral traditions identify the Polynesian explorer Kupe as the first arrival. In some traditions another ancestor, Toi, was also said to be living in Te Ika-a-Māui (the North Island) before the arrival of tribal canoes.
Historians who question the accounts of the early arrival of Kupe and Toi say that these developed from European ideas or Pacific Island sources rather than through Māori oral tradition. These traditions establish both Kupe and Toi as real figures who lived around the time of the settlement canoes – 1300–1400 or later.
Whatever the case, traditions may suggest that discovery preceded large-scale settlement by a considerable period of time. This idea is supported by accounts of tribal canoe voyagers arriving to find Polynesians already living in the North Island.
Explorers may have travelled along the coast without leaving archaeological traces on land. It is possible that some explorers returned to East Polynesia with sailing directions, as told in Māori traditions.
For dating purposes, genealogies are problematic. For example, if you assume the average gap between generations was 20 rather than 25 years, this alters the arrival and settlement dates by more than 100 years. Genealogies can also be highly selective, highlighting or bringing in some ancestors and not mentioning others. In addition, there are complex kinship patterns in Māori society; genealogies did not always follow parent–child relationships.
While oral traditions provide no exact date for arrival or settlement, they do provide an interesting strand of knowledge to compare with other types of evidence. Whether it is coincidence or not, the timing of settlement identified in oral traditions (1325–1400, assuming 25 years per generation) broadly agrees with the findings of radiocarbon dating, which indicates permanent Polynesian settlement was established around 1300.
In the 1950s a new method of archaeological analysis, radiocarbon dating, allowed organic materials such as wood, shell or bone to be accurately dated. All living organisms contain a radioactive form of carbon (carbon-14), which decays at a known rate. Therefore, by measuring the amount of carbon-14 a once-living object retains, scientists can determine its age. While the radiocarbon dating method can provide close estimations of age, the figures should not be regarded as exact.
From the 1960s to the 1980s the oldest radiocarbon dates derived from analysis of settlement sites in New Zealand were 1000–1100 CE or even a little earlier. During the 1990s these dates were systematically re-assessed as the technique became better understood, and many problems were found with earlier dates. For example, it was realised that radiocarbon dates obtained from charcoal fragments were often unreliable: the wood could have come from a tree that was hundreds of years old when it was burnt, and so an occupation site would seem much older than it really was. As a result, the reliable dates all belong to the period after 1250.
Ash that has erupted from volcanoes, consisting of volcanic glass, rock fragments and mineral grains, has a distinct chemical makeup. This means it can be analysed to identify and date when eruptions occurred. Ash fallout from the volcanic eruptions at Taupō (known as the Taupō ash) in 232 (± 15 years), and at Tarawera (known as the Kaharoa ash) in 1314 (± 12 years), might have buried existing settlements. In the eastern North Island, archaeological remains of Polynesian occupation have been found immediately above the Kaharoa ash layer. This settlement must have occurred after that eruption. But no similar remains from beneath either the Taupō or the Kaharoa ash layer have yet been uncovered.
Some theories about a settlement date around 1300 are based on environmental factors. From East Polynesia, New Zealand lies in a southerly direction and in a different weather system. The prevailing winds make it difficult to sail non-stop in a straight line from East Polynesia to New Zealand, or from New Zealand to East Polynesia. By dating archaeological evidence of people stopping over at islands on their return journey, it is possible to suggest the date when they might have reached New Zealand.
The Wairau Bar in Marlborough is one of the oldest known archaeological sites in New Zealand. Researchers Tom Higham, Atholl Anderson and Chris Jacomb, who have radiocarbon-dated it at 1288–1300, suggest that some of the oldest burials there could include people born in tropical Polynesia. Science could provide a way to test this idea. A person’s diet in Polynesia is likely to have differed markedly from that at Wairau Bar. By looking at trace elements in teeth and bones, scientists could possibly tell what a person’s diet was likely to have been, and perhaps where they lived. Recently, similar research in Europe used the oxygen content of tooth enamel to conclude that a person buried in England in 2300 BC was actually born in the European Alps.
The Kermadec group and Norfolk Island lie about halfway between East Polynesia and New Zealand, and it is likely that Polynesian explorers returning from New Zealand stopped at these islands on the way. Distinctive New Zealand obsidian, a glassy volcanic rock used for cutting, is found in archaeological sites on the Kermadecs, and may have been carried there by returning voyagers. Radiocarbon dates of archaeological sites could support the theory that New Zealand and its northern satellite islands were settled at about the same time.
Radiocarbon dates for the settlement of the Chatham Islands are currently later than for mainland New Zealand – around 1500. This is consistent with the stages of cautious Pacific exploration: first the Kermadecs, then New Zealand (possibly including as far south as Enderby Island in the subantarctic Auckland Islands), then the Chathams.
By examining pollen it is possible to determine when past changes in vegetation patterns occurred. In New Zealand, scientists such as Janet Wilmshurst and Matt McGlone drill down and collect cores of sediment from peat bogs or lake beds, and analyse the pollen grains preserved in these cores. Sudden changes in the types of pollen in different sediment layers indicate forest clearance by fires lit by the earliest permanent settlers. Although fire episodes are apparent in New Zealand’s pollen records before 1250 CE, they represent only minor forest disturbance. Because they were so small, these earlier fires cannot be confidently attributed to human activities.
Pollen from some North Island sites (collected from beneath the Kaharoa ash layer) suggests that vegetation changes occurred as early as 1280. As this matches the earliest radiocarbon date from an archaeological site (Wairau Bar 1288–1300), some scientists think that settlers began burning the forest soon after they arrived. But there is not enough evidence to say that this burning, just prior to 1300, is definitely attributable to humans. Still, it is interesting to think that if Polynesians had arrived by this time, those on the coast would have been showered with a few centimetres of ash falls from the Kaharoa eruption in about 1314. The ash layer deposited from this eruption is known as the Kaharoa ash, and erupted from the Mt Tarawera massif.
Nearly all New Zealand pollen records, especially those from drier regions, show that by 1300 there was a massive change from predominantly forest species to bracken fern and scrub, with a corresponding increase in charcoal. These widespread vegetation changes were due to settlers burning the forests for kūmara (sweet potato) cultivation, to create living space and to encourage bracken fern growth. The starch-rich underground stems of bracken fern formed an important part of the settlers’ diet.
The Pacific rat, known to Māori as kiore, is a poor swimmer and could only have arrived in New Zealand with humans. In the mid-1990s a scientist radiocarbon-dated Pacific rat bones excavated from caves in both the North and South islands, and came up with dates as early as 50–150 CE. This meant that humans must also have arrived by this time, some of them with rats on board. The discovery was a scientific bombshell and the possibility of such an early arrival caused hot debate.
In a Hawke’s Bay cave known as the Hukanui rock overhang, a single rat bone, reportedly found beneath the ash layer from the Taupō eruption of 232 CE, returned a radiocarbon date of 134–320. This was consistent with its position below the ash layer. The bone, which was excavated in 1959 by an amateur archaeologist, lay in a matchbox in the Dominion Museum for 40 years before it was dated. How the bone got beneath the 232 Taupō ash layer is still in dispute.
However, a second rat bone from the Taupō ash layer at the Hukanui rock overhang was dated at around 1300, and a pigeon bone from the same layer was dated at 3,000 years old. As bones in undisturbed sediment layers should be about the same age, this raised some difficult questions. The veracity of the ‘matchbox bone’ is still being debated.
Researchers such as Atholl Anderson haved raised questions about the reliability of rat bones for radiocarbon dating, including:
If people did arrive as early as 50–150, and introduced the rat, they either died out or did not stay, as there are no other traces of human settlement until 1250–1300.
Although Pacific rats cannot speak, their DNA tells many stories. In the 1990s scientists began to take a closer look at mitochondrial DNA, which is maternally inherited. Variations in DNA from different populations reveal how they are linked, and how long they have been separated. While the DNA of the Pacific rat (kiore) in New Zealand links mainly to rats from the acknowledged Māori homeland of East Polynesia, some DNA shows links to Norfolk Island. New Caledonia is the closest large tropical island to New Zealand. Voyaging canoes might have used Norfolk Island as a stepping stone in a voyage from New Caledonia to New Zealand, or even on a return voyage.
In the period 50–150 CE there were people, and Pacific rats, living in New Caledonia, Fiji, and West Polynesia. But there are no radiocarbon dates showing settlement this early in East Polynesia. So if rats did arrive in New Zealand around 50–150, then in all probability, the people who brought them did not come from East Polynesia but rather from western island groups.
Computer simulations show that it was just as easy for voyaging canoes to sail to New Zealand from New Caledonia, Fiji, or West Polynesia, as it was from East Polynesia. An early canoe landing in New Zealand from this region is a possibility. In such a scenario the crew either left, died, or were all male (and therefore died out) – but the rat survived. Future analysis of DNA from rat bones dated at 50–150 CE from these western island groups may prove revealing.
While this possibility is interesting, the settlement of New Zealand from 1250–1300 was definitely from islands in East Polynesia, as shown by DNA of Māori descendants, and other evidence such as early artefacts.
Forest seeds are commonly eaten by Pacific rats, who leave tooth marks on woody seed cases. These gnawed seed cases, found preserved in sediment and peat deposits, can be radiocarbon-dated as direct evidence of rat presence. Seed cases have so far been dated from sites in Taranaki and the Coromandel. The earliest evidence of seed consumption by rats, dated by radiocarbon, is from the late 13th century, or 700 years ago. Older seed cases show no rat damage. As nibbled seed cases have only been found above or within the Kaharoa ash layer, they must be more recent than 1314 (±12).
Rats also ate land snails. So researcher Fred Brook looked at gnawed fossil shells of native land snails in Northland. The snails survived the rat attacks, and their shells repaired themselves, but they still displayed the tooth damage. Because of this, he was sure that the rat damage did not occur on empty shells at some later date. Brook only found rat-damaged shells dating from 1250 onwards. Shells older than this date displayed no rat damage.
Research on gnawed forest seeds and gnawed snail shells is consistent with the view that rats (and humans) first arrived around 1250–1300. It suggests that the early radiocarbon ages for rat bones may not represent the true age of these rats.
The timing of animal extinctions gives an alternative date for human arrival and settlement. Polynesians hunted large birds, such as moa, to extinction. Early archaeological sites of human settlement, which belong to a period after 1300 CE, contain evidence for the extinction of 11 species of moa and other large birds. The moa possibly died out within 100–200 years of people arriving.
Some researchers, such as Richard Holdaway, have attempted to show that extinctions or population declines of bats, lizards, frogs and smaller birds (petrels, the owlet-nightjar, Finsch’s duck) prior to 1300 may be due to the predatory Pacific rat. This would mean that humans had also been present in this earlier period. But proof of extinctions or population declines is hard to find, as most dead animals leave very little evidence as to what killed them. Because of this the decline of species in New Zealand can only be linked circumstantially with rat predation, if at all. Rat-gnawed snail shells from Northland provide the earliest concrete evidence to date, but these only occur after 1250.
If there were rats in New Zealand before 1300, why is there no evidence of them gnawing on snails and seeds? The research on gnawed seeds and snail shells does not support the theory that rats arrived as early as 50–150.
It is only when many different dating methods, from many different parts of New Zealand, on several different lines of evidence, all converge to show similar results that most scientists will feel comfortable in determining a first arrival date earlier than the generally accepted date of 1250–1300. One problem is the short time since first human arrival in New Zealand. Regardless of whether this was 700 or 2,000 years ago, most dating techniques have their limitations over such short spans, and interpreting results requires extraordinary care.
Acknowledgements to David J. Lowe (University of Waikato), Bruce McFadgen (independent archaeologist) and Janet Wilmshurst (Landcare Research)
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