New Zealand short-tailed bats are small to medium-sized bats. Their head and body length ranges from 2.3 to 3.5 inches (5.8 to 8.9 centimeters). They can weigh from 0.4 to 1.2 ounces (11 to 35 grams). As their name suggests, these bats have a short tail. The nose or snout of New Zealand short-tailed bats is relatively long and it sticks out over the lips.
These bats have unique wing membranes, the thin pieces of skin that form their wings. The parts of the wing membranes that run along the body are thick and leathery. When not flying, these bats can fold their wings beneath this thick membrane part.
Fur color on these bats is typically brown-gray or brownblack, with the tips of the hairs being white to grayish. This gives the bat a frosted look. The fur is velvety, short, and thick. New Zealand short-tail bats have relatively large ears. These bats have thick bodies with short, strong legs. The claws on their feet are pointy and sharp. The thumbs have a large claw with a talon, a sharp hooked claw, at the end and each of the toe claws also has a talon.
New Zealand short-tailed bats are found on New Zealand and some of its offshore islands. New Zealand is made up of two large and many smaller islands in the southwest Pacific Ocean, east of Australia.
NEW ZEALAND SHORT-TAILED BAT HABITAT
New Zealand short-tailed bats are found in moist forests, where they roost, settle or rest. These bats also forage, search, for food along low-growing shrubbery and the coastline. The New Zealand greater short-tailed bat was once found on two islands but it was last sighted in 1967 and is considered extinct.
NEW ZEALAND SHORT-TAILED BAT DIET
New Zealand short-tailed bats eat a broad range of foods. They are omnivores, meaning they eat both plants and animals, which is unusual in bats. Their diet includes flying and resting arthropods, animals without a backbone with jointed legs and segmented bodies, fruit, nectar, and pollen. The bat has a relationship with a rare and parasitic plant, called woodrose, or pua reinga. The flower produces nectar on the forest floor. As the bats move around eating the nectar they pollinate the plants. New Zealand short-tailed bats are the woodrose’s only pollinator. Researchers have also observed New Zealand short-tailed bats sometimes feeding on birds and carrion, animals that have already been killed.
BEHAVIOR AND REPRODUCTION
New Zealand short-tailed bats are active on the ground more than any other species of bat. Like all other bats, they are nocturnal, meaning they are active at night. Several hours after dusk, they begin foraging for food by running along the ground, up trees, and along tree branches.
These bats typically roost in the hollow trees of forests. They have also been found roosting in caves, houses, and in burrows, holes that they dig in the ground. Observations have shown that these bats roost in large groups of 100 to 500 individuals during the day. They also may roost in far smaller groups, and sometimes singly. When the weather becomes cooler, the bats go into a state of inactivity called torpor, but they will come out of their roosts on warmer winter nights to forage, or search, for food.
To find food, New Zealand short-tailed bats use echolocation (eck-oh-loh-KAY-shun), a technique in which the bats detect objects by sending out high-pitched calls and then listening to the reflected sound. They also find prey, animals hunted for food, by listening for movements and using their sense of smell. They commonly hunt prey on the forest floor, often forming burrows or holes under leaf litter in the ground to forage for food. When they tuck their wings away, these bats use the front arms like front legs, which helps them move along the ground.
Female New Zealand short-tailed bats give birth to one offspring once a year. The timing of mating and births appears to vary according to their location. Limited observations of the greater New Zealand short-tailed bat suggest that a single young may be born from spring to autumn.
NEW ZEALAND SHORT-TAILED BATS AND PEOPLE
People have caused a population decline in the New Zealand short-tailed bats, primarily through introducing predators, animals that hunt the bats for food, and destroying the bats’ natural habitat. In stories the Maori (MAH-oo-ree), the original settlers of New Zealand, associate bats with a mythical, night-flying bird that foreshadows death or disaster.
The lesser short-tailed bats play an important role in the continued life of plants in New Zealand. As they feed on nectar and other plant material, they move from plant to plant and spread pollen, the fine grains that contain the male reproductive cells of seed plants. They are the only pollinators of the woodrose, an endangered and unique flower. These bats also are predators on insects that people may consider pests.
The World Conservation Union (IUCN) lists the lesser New Zealand short-tailed bat as Vulnerable, facing a high risk of extinction, and greater New Zealand short-tailed bat as Extinct, no longer existing. The lesser New Zealand short-tailed bat is known to be present on several islands. Populations have declined to about ten populations that may contain only a few thousand individuals.