Specifically, the Wilmshurst team analyzed bone samples by first removing old carbon contamination from the bones.

The new technique allows carbon dating to show that the oldest rats lived on the main islands of New Zealand at about 1280 A.D., which corresponds to the time when humans first populated the region.

Some theories hold that humans up to 1,000 years earlier first populated New Zealand.

The seeds the team studied showed that they came from a time period of from 100 to 3,000 years ago. However, the seeds containing rat tooth marks only showed up less than 780 years ago.

Again, this helps to show that the thirteenth century was a reliable time when humans first arrived in New Zealand.

Additional information on the Wilmshurst study is found in the June 3, 2008, online issue of the journal Proceedings of the National Academy of Sciences. Please turn the page.