Bats are found throughout the world, except in areas of extreme cold. New Zealand has three species of endemic bats – the long-tailed bat, the lesser short-tailed bat and the greater short-tailed bat, which is thought to be extinct. Bats are nocturnal, they rest during the day and are active at night. New Zealand bats like to roost in old large hollow trees and sometimes in caves. Although native bush is their preferred habitat, they can also be found in urban areas. Bats can be found alone but often roost in social groups.
Long-tailed and short-tailed bats do not hibernate. Instead, when it is cold and food supplies are low, they conserve their energy through torpor. Torpor is more common with short-tailed bats and can last for up to 10 days.
Bats are mammals of the order Chiroptera, and apart from our marine mammals such as Hector’s dolphin (Cephalorhynchus hectori), they are New Zealand’s only endemic mammal species. Within this order, there are two suborders: Microchiroptera (microbats) and Megachiroptera (megabats). New Zealand bat species are microbats.
Some distinguishing features of microbats are:
- they use echolocation
- their ears are larger than megabat ears and include a tragus
- they have small eyes
- there is no claw at the second finger of the forelimb
- some species have tails (including the New Zealand species)
- their teeth structure is suited for a diet of insects and small lizards and frogs.
Taxonomy is an ever-evolving science as research techniques improve or change, allowing more information to be gathered. For example, research is currently under way on a new Yinpterochiroptera-Yangochiroptera classification system for bats. It was also only in 2018 that the North Island and South Island long-tailed bat was confirmed as one species.
The long-tailed bat (Chalinolobus tuberculatus) and the short-tailed bat (Mystacina tuberculata) are New Zealand’s two current bat species.
The greater short-tailed bat (Mystacina robusta) species was found on two islands off Stewart Island, but an invasion of ship rats led to its demise and there have been no sightings since 1967. It is now believed to be extinct.
South Island, Stewart Island, Little Barrier Island, Great Barrier Island and Kapiti Island
Greater short-tailed bat
Unknown – thought extinct
Lesser short-tailed bat (divided into three subspecies)
Northern lesser short-tailed bat
Mystacina tuberculata aupourica
At risk – recovering
Two sites in Northland and one on Little Barrier Island
Central lesser short-tailed bat
Mystacina tuberculata rhyacobia
At risk – declining
Northland, the central North Island and Taranaki
Southern (or South Island) lesser short-tailed bat
Mystacina tuberculata tuberculata
At risk – recovering
Whenua Hou/Codfish Island and Fiordland areas
Long-tailed bats are ranked as nationally critical in New Zealand. They inhabit forest edges, feeding above the forest canopy, along forest margins, over farmland, streams and lakes and sometimes even in caves. Long-tailed bats live in smaller social groupings of 20–60 bats and change roost trees most nights. They hunt in the air for small insects such as moths, midges, mosquitoes and beetles and can fly up to 60 kilometres per hour. Their large home range can be up to 100 km2.
Their torso is covered in dark brown to black fur and they weigh only 8–12 grams, with their wings usually spanning about 250 mm.
Little is known about the breeding behaviour of the long-tailed bat, but it is thought that they give birth to only one pup (baby) a year. Only females care for their pup. They gather in maternity roosts, primarily with other mothers. The single pup is born in December, and it takes its first flight from the roost in early January.
There are three subspecies of the New Zealand short-tailed bat, each with a different conservation status. This ancient species is now the only remaining example of the Mystacina family of bats in the world.
Short-tailed bats are a bit larger than long-tailed bats, weighing around 12–15 grams with a wingspan of 230–300 mm, and they have large pointed ears that are good for echolocation. They have mousy-grey coloured fur and a short tail. Short-tailed bats live in large colonies.
They are a deep forest bat and like to roost in old hollow trees. Short-tailed bats are lek breeders – the males will gather in groups and compete for females by singing or calling to attract a mate.
Unusually for bats, our endemic species is also agile on the ground, often foraging for food on the forest floor by using its folded wings as limbs. They are omnivores, eating insects, fruit, nectar and pollen. They are the only known native pollinator of the threatened Hades flower (Dactylanthus taylorii), which gives off a musky sweet smell to attract the bat. Find out more in the article The kākāpō, the bat and the parasitic plant.
Bats use very high-pitched sounds (mostly above the range of human hearing) to navigate. The sounds they make are reflected back, and they use these reflections to locate and avoid objects in their path and to hunt. Only the microbats suborder species use echolocation. Megabats, such as fruit bats, navigate by sight. Other animals such as dolphins and whales also use the same technique underwater. Researchers used this principle to develop radar and sonar during World War 1 and 2.
Using echolocation helps bats determine where an object is as well as its size and other information. The long-tailed bat call includes a relatively low-frequency component, which can be heard by some people.
The short-tailed bat echolocation calls include multiple harmonics. Calls are loudest around 28 kHz. Long-tailed bat calls also include multiple harmonics, including a low-frequency <20 kHz component.
Researchers and citizen scientists use bat detectors to aid their search for bats. These devices can record bat sounds that humans cannot hear.
Discover more about the conservation efforts by scientists, researchers and citizen scientists as they work to ensure the ongoing survival of New Zealand’s only terrestrial mammal.
Discover more about New Zealand’s predator-free vision and the conservation efforts that will also help protect our endangered bats.
The Connected article Can you hear that? provides an overview of sound, briefly addressing: characteristics of sound waves, how the human ear works, hearing loss in humans, how animal ears work, echolocation and sonar.
If bats are in your area, why not start an investigation into designing and making an artificial bat-roosting box? Ensure you have first considered the bats’ needs and habitats, and be careful when installing in a tree. How does this compare to making a wētā house?
Download the Discovering pekapeka – native bats PDF, written for Starters & Strategies by the Allan Wilson Centre. It includes lesson ideas and activities.
Experience the passion that Ali, Senior Biodiversity Ranger, Department of Conservation, has for bats in this YouTube video.
In this video, find out more about the conservation work of scientists in the Waitakere Ranges as they track and trap long-tailed bats.
Auckland Council and Waikato Regional Council have information about bats, including how to hire a bat detector. These can be used to monitor bat sounds that humans cannot hear and to identify where the bats are.
Read the 2019 New Zealand Geographic article Bat signals to find out more about our amazing short-tailed bats and the research being undertaken on them.
The 2013 School Journal article The bat that walks on the ground looks at the short-tailed bat and conservation efforts required to help protect it. The teacher support material (TSM) has detailed suggestions for supporting level 2 reading and writing.
Watch as bats emerge from a bat box. Several of these artificial roosts have been placed in urban areas in Hamilton.
Check out our Pinterest Board of bat related content here.