It now seems certain that the first Māori settlers arrived in New Zealand sometime about 1280 AD.The consistent picture emerging now is that settlement was much later than the old rat bone dates led many people to believe.Furthermore, the reliability of the bone dating has been questioned, with explanations for their anomalously old ages ranging from variations in laboratory pre treatments to bone contamination through either post-mortem processes or dietary- related offsets.
This is a preserved kaka-cracked miro - you can see a distinctive notch on the side from where the bird has gripped the nut, and then a sharp clean cracked surface where the bird has sheared the nut open using its powerful beak. These rat-gnawed seeds provide strong additional evidence for the arrival of rats, and therefore humans, and are an indirect way of testing the veracity of the dates we have done on rat bones.
Rats leave rows of narrow grooves or bite marks on woody seed cases when they gnaw open the seed, and these distinctive teeth marks can be seen with the naked eye.
It also allows the human settlement of New Zealand to be placed more accurately in the context of the broader settlement pattern of East Polynesia.
Dr Wilmshurst and her colleagues are now turning their attention to other islands in East Polynesia where similar controversies exist over the timing of initial human settlement.
The pen is pointing to a rat-gnawed seed found in-situ within the dark sandy layer.
This layer is the distinctive Kaharoa ash which erupted 1314 ±12 AD.This is consistent with other evidence from the oldest dated archaeological sites, Māori whakapapa, widespread forest clearance by fire and a decline in the population of marine and land-based fauna.As the Pacific rat or kiore cannot swim very far, it can only have arrived in New Zealand with people on board their canoes, either as cargo or stowaways.Radiocarbon dating of Pacific rat (kiore) bones and rat-gnawed native seeds have provided compelling new evidence into the timing of New Zealand’s colonisation.The pacific rat (kiore) spread with voyaging humans; therefore, its earliest presence in New Zealand indicates initial human contact.The first people arriving in New Zealand from tropical East Polynesia initiated an immediate and rapid transformation.A precise date for the arrival of the rat helps us to fully understand both the history of human settlement and the past and present ecological impacts of kiore on native fauna and flora.The presence of rat-gnawed seeds in this ash means that 1314 AD provides an upper age limit for initial rat arrival in New Zealand.Image - J Wilmshurst) nuts collected from spit 0-10cm, in Nguroa Bay, North West Nelson.The study, one of the largest studies of its kind, has shown that the country was not visited by humans over 2000 years ago, as some previous research suggests.The work is published in the journal Proceedings of the National Academy of Sciences in the United States.