The pacific rat (kiore) spread with voyaging humans; therefore, its earliest presence in New Zealand indicates initial human contact.
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.
Their results do not support previous radiocarbon dating of Pacific rat bones.
Their study is the first time that the actual sites involved in the original study have been re-excavated and analyzed.