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.The bite marks from rat incisors are well preserved in these seeds which were radiocarbon dated. Image - J Wilmshurst Searching for gnawed seeds is a time consuming and laborious task, a little like looking for a needle in a haystack.
The earliest dates for rat and human arrival are strikingly consistent with the oldest dates from archaeological sites, the first large clearances of forest by fire, and declines or extinctions of marine and land-based fauna.
The width of the teeth marks left on the woody seeds exactly match those of a rat's two front teeth, and cannot be mistaken for any other seed predator.
In our search for rat-gnawed seeds we also found evidence of past native seed predator on the tough little miro () leave their own distinctive signature of opening up these tough little nuts.
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.