Hawaiian Hoary bat
Encyclopedia
The Hawaiian Hoary bat or Ōpeapea (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, while the Hoary bat is considered the most widespread bat in the continental United States.
name for it, ōpeapea, refers to the bat's half taro
leaf, canoe
sail
body outline. The Hawaiian Hoary bat weighs 5 to 8 oz (141.7 to 226.8 g). The female bats are larger than the males with a wingspan of approximately 10.5 to 13.5 in (26.7 to 34.3 cm).
The Hoary bat is solitary, nocturnal, and feeds
on insect
s. In a single night the Hoary bat can eat up to its own weight in insects.
, Molokai
, Maui
, Oahu
, and Kauai
, but documented breeding currently only takes place on Hawaii and Kauai. A complete extirpation
of Hawaiian Hoary bats on Oahu was hypothesized to be due to a loss of habitat brought about by the land change to accommodate humanity in the 19th century. 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 pesticide
s; the mechanisms are as of yet unknown.
, which was later replaced by the Endangered Species Act of 1973
. 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 and motivated by their rapid extirpation on the island of Oahu, and the loss of forest habitat in the bat’s range. 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 Kauai 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.
has appropriated a recovery plan for the Hawaiian Hoary Bat. The goal of the recovery plan is to de-list the Hawaiian Hoary Bat from endangered status to threatened status 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. 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 that is heard and recorded is from the Hawaiian Hoary bat. So far, echolocation monitoring has worked well because it is non-obtrusive to the bats, which is important when working with an endangered species. 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.
in livable habitats. 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.
Hoary bat
The hoary bat is a species of bat in the vesper bat family, Vespertilionidae. It occurs throughout most of North America and much of South America, with disjunct populations in the Galapagos and Hawaiian Islands...
(family Vespertilionidae
Vesper bat
Vesper bats , also known as Evening bats or Common bats, are the largest and best-known family of bats. They belong to the suborder Microchiroptera . There are over three hundred species distributed all over the world, on every continent except Antarctica...
) that is endemic to the Hawaiian Islands
Hawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
. It is the only land mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
that is endemic to the islands, while the Hoary bat is considered the most widespread bat in the continental United States.
Description
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 HawaiianHawaiian language
The Hawaiian language is a Polynesian language that takes its name from Hawaii, the largest island in the tropical North Pacific archipelago where it developed. Hawaiian, along with English, is an official language of the state of Hawaii...
name for it, ōpeapea, refers to the bat's half taro
Taro
Taro is a common name for the corms and tubers of several plants in the family Araceae . Of these, Colocasia esculenta is the most widely cultivated, and is the subject of this article. More specifically, this article describes the 'dasheen' form of taro; another variety is called eddoe.Taro is...
leaf, canoe
Outrigger canoe
The outrigger canoe is a type of canoe featuring one or more lateral support floats known as outriggers, which are fastened to one or both sides of the main hull...
sail
Sail
A sail is any type of surface intended to move a vessel, vehicle or rotor by being placed in a wind—in essence a propulsion wing. Sails are used in sailing.-History of sails:...
body outline. The Hawaiian Hoary bat weighs 5 to 8 oz (141.7 to 226.8 g). The female bats are larger than the males with a wingspan of approximately 10.5 to 13.5 in (26.7 to 34.3 cm).
The Hoary bat is solitary, nocturnal, and feeds
Insectivore
An insectivore is a type of carnivore with a diet that consists chiefly of insects and similar small creatures. An alternate term is entomophage, which also refers to the human practice of eating insects....
on insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s. In a single night the Hoary bat can eat up to its own weight in insects.
Habitat and range
The fossil record indicates that the Hawaiian Hoary bat was once present on the islands of HawaiiHawaii (island)
The Island of Hawaii, also called the Big Island or Hawaii Island , is a volcanic island in the North Pacific Ocean...
, Molokai
Molokai
Molokai or Molokai is an island in the Hawaiian archipelago. It is 38 by 10 miles in size with a land area of , making it the fifth largest of the main Hawaiian Islands and the 27th largest island in the United States. It lies east of Oahu across the 25-mile wide Kaiwi Channel and north of...
, Maui
Maui
The island of Maui is the second-largest of the Hawaiian Islands at and is the 17th largest island in the United States. Maui is part of the state of Hawaii and is the largest of Maui County's four islands, bigger than Lānai, Kahoolawe, and Molokai. In 2010, Maui had a population of 144,444,...
, Oahu
Oahu
Oahu or Oahu , known as "The Gathering Place", is the third largest of the Hawaiian Islands and most populous of the islands in the U.S. state of Hawaii. The state capital Honolulu is located on the southeast coast...
, and Kauai
Kauai
Kauai or Kauai, known as Tauai in the ancient Kaua'i dialect, is geologically the oldest of the main Hawaiian Islands. With an area of , it is the fourth largest of the main islands in the Hawaiian archipelago, and the 21st largest island in the United States. Known also as the "Garden Isle",...
, but documented breeding currently only takes place on Hawaii and Kauai. A complete extirpation
Local extinction
Local extinction, also known as extirpation, is the condition of a species which ceases to exist in the chosen geographic area of study, though it still exists elsewhere...
of Hawaiian Hoary bats on Oahu was hypothesized to be due to a loss of habitat brought about by the land change to accommodate humanity in the 19th century. 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 pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...
s; the mechanisms are as of yet unknown.
Endangered status
In 1970, the Hawaiian hoary bat was listed as an endangered species under the Endangered Species Conservation Act of 1969Endangered Species Act of 1969
The Endangered Species Act of 1969 was an expansion of the Endangered Species Preservation Act of 1966 which authorized the United States Secretary of the Interior to develop a comprehensive list of species or subspecies of animals threatened with worldwide extinction...
, which was later replaced by the Endangered Species Act of 1973
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
. 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 and motivated by their rapid extirpation on the island of Oahu, and the loss of forest habitat in the bat’s range. 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 Kauai 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 Nature Conservancy
The Nature Conservancy is a US charitable environmental organization that works to preserve the plants, animals, and natural communities that represent the diversity of life on Earth by protecting the lands and waters they need to survive....
, the United States Fish and Wildlife Service
United States Fish and Wildlife Service
The United States Fish and Wildlife Service is a federal government agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats...
, and independent researchers.
Recovery plan
The United States Fish and Wildlife ServiceUnited States Fish and Wildlife Service
The United States Fish and Wildlife Service is a federal government agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats...
has appropriated a recovery plan for the Hawaiian Hoary Bat. The goal of the recovery plan is to de-list the Hawaiian Hoary Bat from endangered status to threatened status 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. 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
Echolocation
Echolocation may refer to:* Acoustic location, the general use of sound to locate objects* Animal echolocation, non-human animals emitting sound waves and listening to the echo in order to locate objects or navigate...
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 that is heard and recorded is from the Hawaiian Hoary bat. So far, echolocation monitoring has worked well because it is non-obtrusive to the bats, which is important when working with an endangered species. Another approach that is being looked into is that of putting GPS trackers
GPS wildlife tracking
GPS wildlife tracking is a process whereby biologists, scientific researchers or conservation agencies can remotely observe relatively fine-scale movement or migratory patterns in a free-ranging wild animal using the Global Positioning System and optional environmental sensors or automated...
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.
Outlook
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 diversityBiodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...
in livable habitats. For these reasons the conservation
Conservation biology
Conservation biology is the scientific study of the nature and status of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction...
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.