The most damage however was caused by habitat destruction and the other animals humans brought with them, particularly rats (the Polynesian rat or kiore introduced by Māori and the Brown Rat and Black Rat subsequently introduced by Europeans), but also mice, dogs, cats, stoats, weasels, pigs, goats, deer, hedgehogs, and Australian possums.
According to the traditions of the Aotea, Horouta and Māmari ancestral canoes, kiore (Polynesian rats) were passengers on their voyages from Hawaiki to New Zealand.