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Order: Chiroptera
Family: Rhinolophidae
Horseshoe and Old World leaf bats are clearly closely related, and are usually placed together in a single family, the Rhinolophidae. Within this family they are separated into two subfamilies, the Hipposiderinae (horseshoe bats) and Rhinolophinae (Old World leaf-nosed bats), although some researchers argue that the two groups are sufficiently distinct for the horseshoe bats to be placed in a separate family, the Hipposideridae.
Imaizumi's horseshoe bat belongs to the subfamily Rhinolophinae, which includes a single genus Rhinolophus containing 77 species. This group of bats is thought to date back as far as the middle Eocene (45 million years ago).
Size:
Head and body length: 35-110 mm
Tail length: 15-56 mm
Forearm length: 30-75 mm
Tail length: 15-56 mm
Forearm length: 30-75 mm
Weight: approx. 4-28 g
Colour varies greatly amongst the bats in this genus, ranging from reddish-brown to deep black above and paler below. All species have a peculiar, complex ‘nose-leaf’, the lower part of which is horseshoe-shaped (hence the common name “horseshoe bats” for this group of bats). This nose-leaf may function in orientating the ultrasonic sounds these bats emit through their nostrils. The ears are large and pointed, and the eyes are quite small. The field of vision seems to be partly obstructed by the large nose-leaf, so sight is probably of little importance. The wings are broad with rounded ends.
Horseshoe bats feed mostly on insects and spiders. They usually hunt within six metres of the ground and will also feed on the ground. Their relatively short tails and small tail-membranes are not large enough to form a pouch for holding insects. When a large insect is caught in flight, it may be tucked into the wing membrane under the arm while the bat manipulates it with its mouth. They often return to the roost to eat their catch. Most species roost in moderate-sized groups, but some are solitary.
In general Rhinolophus gestation takes about seven weeks, a single young is produced in late spring, and sexual maturity is attained by two years. These bats rarely live longer than 6-7 years.
Horseshoe bats are known to roost in caves, buildings, foliage and hollow trees. This species has been recorded from areas of temperate forest.
Iriomote Island (southern Ryukyu Islands), Japan.
Unknown.
Declining.
Classified as Endangered (EN A2c, B1+2abcde) on the 2006 IUCN Red List of Threatened Species.
The species is thought to be declining rapidly because of human habitat disruption. A large population is known from a cave system beside a national forest. However, there has been pressure to convert areas of the forest to agriculture, which would remove key foraging areas and result in potential isolation of the cave roosts. Publicity about the plight of bats inhabiting the caves system has resulted in increased public interest, including increased tourism to the breeding caves, which may also be having a negative impact.
There have been some surveys on Iriomote Island which are attempting to integrate economic development with the conservation of bats.
No official conservation recommendations have been made.
Chiroptera Specialist Group. 1996. Rhinolophus imaizumii. In: IUCN 2006. 2006 IUCN Red List of Threatened Species. Downloaded on 24 November 2006.
Hutson, A. M., Mickleburgh, S. P. and Racey, P. A. (Compilers). 2001. Microchiropteran Bats: Global Status Survey and Conservation Action Plan. IUCN/SSC Chiroptera Specialist Group. IUCN: Gland, Switzerland.
Nowak, R.M. 1999. Walker's Mammals of the World. Sixth edition. The Johns Hopkins University Press, Baltimore and London.
Distribution map based on data provided by the IUCN Global Mammal Assessment.
Hutson, A. M., Mickleburgh, S. P. and Racey, P. A. (Compilers). 2001. Microchiropteran Bats: Global Status Survey and Conservation Action Plan. IUCN/SSC Chiroptera Specialist Group. IUCN: Gland, Switzerland.
Nowak, R.M. 1999. Walker's Mammals of the World. Sixth edition. The Johns Hopkins University Press, Baltimore and London.
Distribution map based on data provided by the IUCN Global Mammal Assessment.
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