Trefoil horseshoe bat  (Rhinolophus trifoliatus)

This striking and charismatic bat is identifiable by its yellow noseleaf and long, soft, fluffy, greyish-brown fur. The elbows, knees and ears are also yellow, deepening in colour with age. The wings are a light, almost orangey brown, and the membrane also stretches between the hind legs, enclosing most of the tail. As a member of the horseshoe bat family, the noseleaf of this species is shaped like a horseshoe, with a projection that looks somewhat like the horn above it (3). This serves to focus the ultrasonic pulses during echolocation. The ears are large and highly mobile to receive the echoes (4).

The trefoil horseshoe bat is found in Brunei, India, Java, Kalimantan, Sumatra, Peninsular Malaysia, Borneo, Burma, Singapore and Thailand (1). Subspecies include Rhinolophus trifoliatus niasensis on Nias Island (5).

Occupying primary, secondary, and mangrove forest, the trefoil horseshoe bat feeds amongst the vegetation of the understorey and roosts there alone under dead leaves and palms. It has also been found in caves (2).

An insectivore, the trefoil horseshoe bat catches its prey by ‘perch hunting'; it hangs from a branch at a height of around three metres above the forest floor, with a clearing beneath, and waits for insects to pass. Once it has detected them using echolocation, emitted from the noseleaf, it drops from the perch and pursues the insect, returning to a hanging position to eat it (2) (3). This species uses long pulses of a constant frequency to detect the flutter of an insect's wings (4).

The trefoil horseshoe bat gives birth to a single pup which it suckles for several months before the pup is able to fly and catch insects alone. The pup begins life weighing 2- 5 grams; a large proportion of its mother's weight. By one year of age it is fully grown and ready to have a pup of its own (3).

The rapid increase in land devoted to growing oil palm has resulted in extensive loss of primary forest. Together, Malaysia and Indonesia export 88% of the world's palm oil, for use in products such as margarine, lipstick and detergent. Deforestation continues at a steady rate for conversion to agricultural land and building communities, and despite the contribution of many bats in the control of insect crop pests, persecution of bats is also a threat (6).

Deforestation of primary forest for oil palm plantations, including within protected areas, is an issue of major concern and one that relies on both governmental action and consumer concern. Some large retailers have agreed, in collaboration with the WWF, to source products containing palm oil from plantations that are not on deforested land (6). Many scientific and charitable groups contribute to bat monitoring and local education programmes that can help to reduce persecution and raise awareness of the natural assets of the land (3).

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk