| Hawaiian Hoary bat | |
|---|---|
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Chiroptera |
| Family: | Vespertilionidae |
| Genus: | Lasiurus |
| Species: | L. cinereus |
| Subspecies: | L. cinereus semotus |
| Trinomial name | |
| Lasiurus cinereus semotus (H.Allen, 1890) |
|
The Hawaiian Hoary bat or ʻŌpeʻapeʻa (Lasiurus cinereus semotus) is a subspecies of the Hoary bat (family Vespertilionidae) that is endemic to the Hawaiian Islands. It is the only land mammal that is endemic to the islands,[2] while the Hoary bat is considered the most widespread bat in the continental United States.[3]
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The Hoary bat is named after the animal's appearance: "Hoary" describes the fur of the bat, which is brown and grey, tinged with white, so that the bat looks "frosty." The Hawaiian name for it, ʻōpeʻapeʻa, refers to the bat's half taro leaf, canoe sail body outline.[2] The Hawaiian Hoary bat weighs 5 to 8 ounces (140 to 230 g). The female bats are larger than the males with a wingspan of approximately 10.5 to 13.5 in (27 to 34 cm).[4] The Hoary bat is solitary, nocturnal, and feeds on insects. In a single night the Hoary bat can eat up to its own weight in insects.[2]
The fossil record indicates that the Hawaiian Hoary bat was once present on the islands of Hawaiʻi, Molokaʻi, Maui, Oʻahu, and Kauaʻi, but documented breeding currently only takes place on Hawaiʻi and Kauaʻi. A complete extirpation of Hawaiian Hoary bats on Oʻahu was hypothesized to be due to a loss of habitat brought about by the land change to accommodate humanity in the 19th century.[5] Much of the forest was cut down to make room for houses and buildings. On top of habitat change the Hawaiian Hoary Bats' populations appear to be indirectly affected by the use of pesticides; the mechanisms are as of yet unknown.[6]
In 1970, the Hawaiian hoary bat was listed as an endangered species under the Endangered Species Conservation Act of 1969,[7] which was later replaced by the Endangered Species Act of 1973.[8] Under section 3 of the endangered species act, an "endangered species" is any species or subspecies that is "in danger of extinction throughout all or a significant portion of its range." The exact number of Hawaiian Hoary bats is unclear and remains unknown. The decision to add the Hawaiian Hoary bat to the endangered list seems to have been precautionary[9] and motivated by their rapid extirpation on the island of Oʻahu, and the loss of forest habitat in the bat’s range.[10] Till this day there exists conflict on the decision to list to Hawaiian Hoary bat as endangered. According to Fuller, 1989 who surveyed the island of Kauaʻi for Hawaiian Hoary bats, "the Hawaiian Hoary Bat is deserving of its endangered status" while others such as the article written in Plants and animals of Hawaii by S. Scott (1991) claim that "although the Hawaiian Hoary bat is on the federal endangered list, it may not truly be endangered." Until exact numbers of the Hawaiian Hoary bats are found, uncertainty over whether or not the bat should be listed as endangered is a matter of opinion. However, since the Hawaiian Hoary bat was listed in the 1970s conservation has been underway by the Nature Conservancy, the United States Fish and Wildlife Service, and independent researchers.
The United States Fish and Wildlife Service has appropriated a recovery plan for the Hawaiian Hoary Bat.[11] The goal of the recovery plan is to de-list the Hawaiian Hoary Bat from endangered status to threatened status[12] however, due to the lack of understanding of the life history of the bats, more information is needed to conclude effective numbers for de-listing the bat. According to the recovery plan, all islands that have Hawaiian Hoary bats must have increasing populations for at least 5 consecutive years to be considered for downlisting to threatened status.[12] New methods are being developed to try to get a good estimate of the population numbers of Hawaiian Hoary Bats. One method that looks promising is monitoring the bats' echolocation calls. Unlike most parts of the world where there are other species of bats whose calls would interfere with the hoary bat's echolocation transmissions, the Hawaiian hoary bat is the only species of bat found in Hawaii so any echolocation transmission[13] that is heard and recorded is from the Hawaiian Hoary bat.[14] So far, echolocation monitoring has worked well because it is non-obtrusive to the bats, which is important when working with an endangered species.[15] Another approach that is being looked into is that of putting GPS trackers on the bats to try to gain a better understanding of their life histories and strategies. However, since the bats are small it is hard to outfit them with trackers without potential side effects of the already endangered bat.[4]
Although not much reliable information is known about the Hawaiian Hoary Bat, its prognosis for survival seems high because it is found on multiple islands, there have been frequent individual sightings, and it can be found in both native and non-native plant habitats; which shows diversity in livable habitats.[16][17] For these reasons the conservation of the Hawaiian Hoary Bat seems probable, and possible. By the year 2010, the US Fish and Wildlife Service hopes to have the Hawaiian Hoary Bat listed as threatened and not endangered.[12]