Hawaiian Hoary Bat

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Hawaiian Hoary Bat

Lasiurus cinereus semotus

ListedOctober 13, 1970
FamilyVespertilionidae (Bats)
DescriptionSmall reddish bat.
HabitatWoodlands, groves, open fields for foraging.
ReproductionTwo young per season.


The Hawaiian hoary bat, Lasiurus cinereus semotus, is a light reddish gray and averages less than 4.5 in (11 cm) in length. When it moves, the bat's coloration appears to ripple as the darker underfur is exposed. This subspecies is smaller and more reddish than related mainland forms. It and the Endangered Hawaiian Monk Seal (Monachus schauinslandi ) were the first mammals to establish populations on the Hawaiian Islands.


The Hawaiian hoary bat feeds primarily on insects. It is non-social, nesting and foraging singly. As cooler winter weather approaches, the bat stores up to 25% of its body weight in additional fat reserves, suggesting hibernation, although no bats have been observed to hibernate. Between May and July the female bears two young, which she carries piggy-back until they are almost fully grown.


This forest-dwelling species roosts in trees or rock crevices. It forages in forest clearings, in open fields at the forest edge, and sometimes above agricultural lands, such as sugarcane fields or Macadamia nut groves. Bats along the coast have been observed catching insects over the open ocean. Habitat elevation typically ranges from sea level to about 3,940 ft (1,200 m), although bats have occasionally been found at higher altitudes.


This species is endemic to the Hawaiian Islands and probably evolved from stray migratory mainland bats, developing its unique characteristics more than 10,000 years ago.

The Hawaiian hoary bat is considered most abundant on the islands of Kauai and Hawaii. Occasional individuals are reported from Oahu and Maui. No record exists of bats on Molokai or Lanai. Although little information is available, an estimate made in the 1970s placed the size of the population at several thousand. The population on the island of Hawaiithe only one that has been studiedwas thought to be small but stable.


Loss of native forests at lower altitudes has caused an overall decline in the number of Hawaiian hoary bats, but in some areas habitat loss has been balanced by the bat's ability to use agricultural lands for foraging. Because individuals are highly scattered, the total population may be larger than it appears. No systematic research has been conducted on the natural history and abundance of this species. State biologists consider it rare but not particularly in danger on Kauai. Therefore, it has been accorded a low priority by the Division of Forestry and Wildlife.

Conservation and Recovery

In 1994, the U. S. Fish and Wildlife Service (FWS) entered into a cooperative agreement with federal, state, and private agencies providing for cooperative management of thousands of acres (thousands of hectares) of native forest on the island of Hawaii near Kilauea volcano. This area provides habitat for many native Endangered Hawaiian species, including the Hawaiian hoary bat, four forest birds, and several plants. Other cooperators in the agreement include the Kamehameha Schools Bishop Estate (the largest private landowner in the state), the Hawaii Department of Public Safety, the Hawaii Division of Forestry and Wildlife, and the National Park Service (Hawaii Volcanoes National Park).

Ultimately, the FWS hopes to use this cooperative agreement and its partnerships as a means to provide some protection for the 100 sq mi (259 sq km) of forest in the Kilauea area. Before its implementation, informal discussions had been going on for several years about how to manage the natural resources of this area given its fragmented ownership. The partners hope this agreement is the start of a cooperative relationship between landowners in the area and natural resource agencies to find innovative ways of increasing environmental protection for Hawaii's native species.


Regional Office of Endangered Species
U.S. Fish and Wildlife Service
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181


Thornback, J., and M. Jenkins. 1982. The IUCN Mammal Red Data Book, Pt. 1. International Union for the Conservation of Nature and Natural Resources, Gland, Switzerland.

Tomich, P. Q. 1965. "The Hoary Bat in Hawaii." Elepaio 25(11):85-86.

Tomich, P. Q. 1974. "The Hawaiian Hoary Bat: Dare-devil of the Volcanoes." National Parks and Conservation Magazine 48(2):10-13.

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Hawaiian Hoary Bat

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