Dating the late prehistoric dispersal of Polynesians to New Zealand using the commensal Pacific rat

Janet M. Wilmshurst, Atholl J. Anderson, Thomas F.G. Higham, Trevor H. Worthy

Research output: Contribution to journalArticlepeer-review

418 Citations (Scopus)


The pristine island ecosystems of East Polynesia were among the last places on Earth settled by prehistoric people, and their colonization triggered a devastating transformation. Overhunting contributed to widespread faunal extinctions and the decline of marine megafauna, fires destroyed lowland forests, and the introduction of the omnivorous Pacific rat (Rattus exulans) led to a new wave of predation on the biota. East Polynesian islands preserve exceptionally detailed records of the initial prehistoric impacts on highly vulnerable ecosystems, but nearly all such studies are clouded by persistent controversies over the timing of initial human colonization, which has resulted in proposed settlement chronologies varying from ≈200 B.C. to 1000 A.D. or younger. Such differences underpin radically divergent interpretations of human dispersal from West Polynesia and of ecological and social transformation in East Polynesia and ultimately obfuscate the timing and patterns of this process. Using New Zealand as an example, we provide a reliable approach for accurately dating initial human colonization on Pacific islands by radiocarbon dating the arrival of the Pacific rat. Radiocarbon dates on distinctive rat-gnawed seeds and rat bones show that the Pacific rat was introduced to both main islands of New Zealand ≈1280 A.D., a millennium later than previously assumed. This matches with the earliest-dated archaeological sites, human-induced faunal extinctions, and deforestation, implying there was no long period of invisibility in either the archaeological or palaeoecological records.

Original languageEnglish
Pages (from-to)7676-7680
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number22
Publication statusPublished - 3 Jun 2008
Externally publishedYes


  • Archaeological visibility
  • Colonization
  • East Polynesia
  • Radiocarbon
  • Rattus exulans


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