The New Zealand lesser short-tailed bat is a small-sized omnivorous mammal endemic to the islands of New Zealand. It is one of two extant and three overall terrestrial mammal species unique to New Zealand. Its closest relative, the New Zealand greater short-tailed bat, was last seen in 1965 and is presumed extinct due to intense predation from ship rats introduced in the last few centuries. These bats are also commonly referred to as pekapeka, their Māori-language name. Lesser short-tailed bats have unique adaptations that differentiate them from bats found in other parts of the world. For example, they are fully capable of moving along the ground to search for food, and the males sing to attract partners, taking turns to do so. Lesser short-tailed bats are a vulnerable species, so extensive conservation work and research are being done to prevent extinction.

The New Zealand greater short-tailed bat is one of two species of New Zealand short-tailed bats, a family (Mystacinidae) unique to New Zealand. Larger than the New Zealand lesser short-tailed bat, there have been no confirmed sightings of this species since 1965 and it is considered to be critically endangered, if not extinct. In prehistoric times it lived in the North and South Islands but by the time of European arrival was restricted to small islands near Stewart Island/Rakiura. A rat invasion of Taukihepa/Big South Cape Island in 1963 was thought to have led to the species' extinction, however, recent surveys have raised hopes that the species may still exist.