Ridley’s leaf-nosed bat  (Hipposideros ridleyi)

Classified as Vulnerable (VU) on the IUCN Red List (1).

With a saucer-shaped disc in front of the nostrils, above a contorted horizontal structure known as a ‘nose-leaf’, Ridley’s leaf-nosed bat has a bizarre appearance. The nose-leaf functions to emit ultrasound, used by some bats (mainly Microchiroptera) to orientate, and to locate prey (‘echolocation’). This bat also possesses very large and broad ears with rectangular tips and folded outer edges. The fur is dark brown and extends very slightly onto the wings. The wing membranes are sooty-brown to black and are partly edged with dull yellow colouration. Only the extreme tip of the tail is free from membrane (2).

For many years Ridley’s leaf-nosed bat was known only from the original specimen, caught in Singapore in 1911. In the late 1970s several small colonies of this species were found around Selangor in Malaysia, and it has since been reported from Sabah and Sarawak in North Borneo, as well as Peninsular Malaysia, Sumatra, and Laos (2).

Ridley’s leaf-nosed bat is found in peat swamp forest and primary mixed dipterocarp forest. It is thought to roost in caves and use trails in the understory of lowland dipterocarp forest to move around its habitat (2)

As a result of the small number of observations of this species, knowledge of its biology is extremely limited. It echolocates using ultrasound frequencies of between 65 and 67 kHz to find insects and to orientate itself. It has been noted as lactating between early April and late May (2).

Selective logging throughout the entire range threatens the habitat of Ridley’s leaf-nosed bat. In Laos, bats are exploited for food, regardless of size, and Ridley’s leaf-nosed bat may be particularly vulnerable to this, as it roosts in caves making it possible to capture several bats at once (2).

The documentation of biodiversity in the area and the education of the public, as well as the protection of adequate habitat, are all essential to the survival of this and many other bat species. Malaysia is home to a particularly high diversity of bats, so the protection of its forest habitat may safeguard many other species (2).

• Dipterocarpaceae: a family of resinous trees that are found in the old world tropics.
• Echolocation: detecting objects by reflected sound. Used for orientation and detecting and locating prey by bats and cetacea (whales and dolphins).
• Primary forest: forest that has remained undisturbed for a long time and has reached a mature condition.
• Ultrasound: sounds that are above the range of human hearing.

1. IUCN Red List (December, 2007)
   http://www.iucnredlist.org
2. Robinson, H.C. and Kloss, C.B. (1911) On new mammals from the Malay Peninsula and adjacent islands. Journal of the Federated Malay States Museums, 4: 241 - 243.
3. ITIS (November, 2004)
   http://www.itis.gov