Prior to human settlement, the mammals of New Zealand consisted entirely of several species of bat, and several dozen marine mammal species (though the Miocene Saint Bathans Mammal shows that at some point there were terrestrial, "archaic" mammal species). The Māori brought the kurī (Polynesian dog) and kiore (Polynesian rat) in about 1250 CE, and Europeans from 1769 onwards brought the pig, sheep, mice, two additional species of rats, weasels, stoats, ferrets and possums and many other species, some of which cause conservation problems for indigenous species.

There are three species of bat: the long-tailed bat, the lesser short-tailed bat, and greater short-tailed bat. The greater short-tailed bat is thought to be extinct. The long-tailed bat and short-tailed bat are classed as 'critical/vulnerable'. They are in danger of extinction in the medium term if nothing is done to reverse their population declines. These species are a high priority for conservation.

Maori folklore refer to bats as pekapeka and associate them with the mythical, night-flying bird, hokioi, which foretells death or disaster.

More Info: en.wikipedia.org