Hawaiian Hoary Bat

Lasirus cinereus semotus / ‘ope‘ape‘a
Hawaiian hoary bat

The ‘ope‘ape‘a weighs 14 to 18 g (0.49 to 0.63 ounces) with a wing span of about 10.5 to 13.5 inches. Females are larger than males. The bat is nocturnal and feeds on a variety of native and nonnative night-flying insects.

Bats are found primarily from sea level to 2,288 m (7,500 ft), although they have been observed near the island's summits above 3,963 m (13,000 ft). Relatively little research has been conducted on this endemic ‘ope‘ape‘a and data regarding its habitat and population status are very limited. Most of the available documentation suggests that this elusive bat roosts among trees in areas near forests.

It is a solitary bat that typically leaves its roost shortly before or after sunset and returns before sunrise. Breeding has only been documented on Hawai‘i and Kaua‘i. Like their North American relative, the ‘ope‘ape‘a gives birth to twins during the summer months.

The ‘ope‘ape‘a has been seen on the islands of Hawai‘i, Maui, Moloka‘i, O‘ahu, and Kaua‘i, but may only live on Hawai‘i, Maui, and Kaua‘i. A large population might have lived on O‘ahu before the early 19th century, but it is based on a single observation of an unknown number of bats.

Population estimates for all islands have ranged from hundreds to a few thousand, however, these estimates are based on limited and incomplete data. The magnitude of any population decline is unknown. Observation and specimen records do suggest, however, that these bats are now absent from historically occupied ranges.

‘Ope‘ape‘a populations are believed to be threatened by habitat loss, pesticides, predation, and roost disturbance. The ‘ope‘ape‘a was listed as an endangered species on October 13, 1970, under the Federal Endangered Species Act and the State of Hawai‘i's Endangered Species List.

Facts About Hawaiian Hoary Bat

It has a heavy fur coat that is brown and gray, and ears tinged with white, giving it a frosted or "hoary" look. It is believed to be related to the North American hoary bat and it is the only native land mammal of Hawai‘i.