A publication of the Archaeological Institute of America
Can Rats Rewrite Pacific History?
"Early rats--yes or no?" Some seventy archaeologists shift uneasily in their seats, focusing on a slight man at the front of a small auditorium. On the second day of the New Zealand Archaeological Association's (NZAA) annual meetings, Nigel Prickett of the Auckland Museum has sprung an impromptu poll touching on two of the country's most sensitive archaeological questions. When did settlers ancestral to today's Maori arrive in New Zealand, and were they the first to introduce rats to its islands? Or were rats, which are not native to New Zealand, already there, left behind by earlier voyagers who are not yet visible in the archaeological record?
"Not the bloody rats again," someone murmurs, tearing a piece of paper from his notebook. The archaeologists scribble their answers and pass them forward--anonymity is assured.
The Pacific rat (Rattus exulans), called kiore in Maori, is considered proxy evidence for human settlement throughout the Pacific. Rats are not native to Polynesia and they cannot swim, so they must have been transported from island to island as stowaways or as food on the great canoes the Polynesians piloted across the ocean. In 1996, biologist and avian paleontologist Richard Holdaway published a paper that presented radiocarbon dates on rat bones from nonarchaeological sites in New Zealand. The bones came from deposits that were created by birds, most likely owls. Holdaway's dates showed rats in the New Zealand archipelago nearly 2,000 years ago, implying humans had visited New Zealand at the same time. His data was criticized on several fronts. Objections were raised concerning the poor preservation of the rat bones, and critics pointed out that rat diet and the contamination of the bone by ancient carbon could have thrown off the dates.
Some six years later, Holdaway wearily recalls the backlash. "My career was threatened. I was told initially that I couldn't possibly understand the ramifications of my dates, they were obviously wrong. I could not legitimately publish them with my interpretation. If they were published at all they had to be published as a simple list, and archaeologists would sort out what it all meant. It was an extreme affront to a scientist--that he couldn't possibly interpret his own data."
Holdaway makes no claims for permanent early settlement, concluding that the rats were left behind by explorers who either failed or did not attempt colonization. He points out that had early explorers stayed for any significant period of time, they would have devastated the local fauna, particularly the flightless moa, an event that surely would have shown up in the archaeological record (see "No Moa: Modeling an Extinction," ARCHAEOLOGY Online, March 2000). He thinks the people who introduced the kiore stayed only a few years at most.
Even if the rat dates are correct, people have been in New Zealand for less time than they have any other large landmass on the globe except for Antarctica, making the islands' history the briefest of stints in the long human record. But reminders of the richness of that short span are everywhere, and not just in museum collections. Just south of the Auckland Museum, the sites of fortified Maori hilltop villages, or pas, rise above the suburbs atop magnificent volcanic cones. Standing in the center of Auckland, where pas and skyscrapers share the landscape, it's clear to even the most casual tourist that plenty has happened in New Zealand, brief as its history has been.
Eric A. Powell is an associate editor of ARCHAEOLOGY.