Hawaiian Hoary Bat

## Description

The Hawaiian hoary bat is the only extant and native terrestrial mammal found in Hawaiʻi. Like many species of bats, Hawaiian hoary bats are brown in color. However, they are distinguished by a silver tint along the brown fur of their backs. More pronounced silver bands are found along the necks as the fur transitions to a yellowish brown along the face with the ears retaining a black edging around their perimeter. The common name of hoary bats was inspired by the hoary, or frosty, the coloration of their coats. Females of this species are larger than males.

## Distribution

These bats are native to the islands of Hawaiʻi. They are found in landscapes including human-populated areas, forests, agricultural fields, pastures, and even near mountain summits. During the warmer months, bats will travel to lowland environments where they will be more active. During the colder months, Hawaiian hoary bats travel to highland environments where they are not as active.

## Behavior

Hawaiian hoary bats are solitary and prefer to roost individually rather than in colonies. They are nocturnal hunters, usually hunting for food just before sunset and returning to their nests just before sunrise. Like other bats, they capture and eat their prey while still in flight. Bats do not have keen eyesight to spot their prey; rather, they use echolocation. By foraging using echolocation, bats can catch their target while in flight. The bats’ flight patterns differ in accordance to the environment they are hunting in and the prey they are hunting. When hunting in open environments (i.e pastures or above the canopy) where larger prey is more abundant, they will fly faster with less maneuverability. When hunting in closed environments (i.e clustered forests) where smaller prey is more abundant, they will fly slower to allow for more maneuverability to catch their elusive prey. While foraging, Hawaiian hoary bats can travel up to 19 km (12 miles) a night.

## Diet

Hawaiian hoary bats are carnivores (insectivores) preying on insects for their source of food. They feed mainly on moths and beetles, but also eat crickets, mosquitoes, termites, and many other insects.

## Reproduction

Hawaiian hoary bats are serially monogamous. They don’t mate for life but have a new partner each mating season. They follow a seasonal reproductive cycle. Mating occurs from October to November. The gestation period begins in May and ends in June when the lactation period begins. Pups are born at the end of August and will remain in the mother’s roosting nest until they become independent in 6 to 7 weeks. Female Hawaiian hoary bats usually give birth to twins.

## Population

### Threats

The main threats to Hawaiian hoary bats include habitat loss, collisions with man-made structures such as wind turbines and barbed wire, the impact of pesticides on the primary food sources, predation and competition with invasive species, roost disturbance, and tree cover reduction.

### Number

Due to their elusive and solitary nature, there is little research on the life history of the Hawaiian hoary bat. According to a Wikipedia resource in 2005, it was estimated that the population size of this species ranged from a few hundred to a few thousand individuals, but this was based on incomplete and inadequate data. As of January 2020, population sizes and estimates are still unknown. Presently, the Hawaiian hoary bat is not included in the IUCN Red List and its conservation status has not been evaluated.

## Fun Facts

The Hawaiian hoary bat was officially named the state land mammal of Hawaiʻi in 2015.

Hawaiian name o this bat, ʻōpeʻapeʻa ("half-leaf", also the shape of a traditional Hawaiian sail), refers to the outline of its body, which is shaped like half a taro leaf.

Hawaiian hoary bats always remember their roosts and foraging locations and return to them repeatedly.