Bonin Fruit Bat (Bonin Flying Fox)
At dusk, black silhouettes dot the sky as large bats take flight on their nightly search for food. The Bonin fruit bat is the only mammal native to the Ogasawara Islands and can be found only on Chichijima, Hahajima, and the Iwo Islands. The bats have long, silver-tipped black and brown fur on their heads, backs, and bellies, but their wings are hairless. The wingspan of mature bats can reach over 80 centimeters.
Before people arrived on the islands, the bats ate the fruit of the pandanus tree (tako-no-ki), other small fruits, and native flowers. Today, they seem to be more interested in the mangoes and citrus fruits grown by local farmers. The bats are endangered, and it is illegal to harm them, but living in harmony with the bats is challenging for some of the islanders. Farmers on the islands try to protect their crops with soft netting, but the bats get tangled in it and can be injured as they struggle to free themselves. To protect the bats, the Japanese government, the local government, and conservation groups are working to help farmers install rigid netting to cover their crops while keeping the bats safe. For injured bats, there is also a rehabilitation facility on Chichijima that provides treatment before returning them to the wild.
The Bonin fruit bat is endangered primarily because of habitat loss. During the day, the bats roost in dense stands of trees, which protect them while they rest and mate. After Ogasawara was cleared to make room for farms and houses, however, little habitat remained for the bats. As a part of efforts to protect their remaining habitats and revitalize the population on Chichijima, it is prohibited to enter their roosting stands without sufficient reason.
Although not strictly prohibited, it is strongly recommended that visitors are accompanied by a trained guide when going on a bat-watching tour. Without the instruction of a guide, visitors may inadvertently disturb the Bonin fruit bats in their roosting stands, which can cause them to abandon the area completely. Additionally, it may be difficult to locate the bats without prior knowledge of where to find them.