Lesser brown horseshoe bat  (Rhinolophus stheno)

As a medium-sized member of the horseshoe bat family, this species is characterised by its complex noseleaf. Consisting of a broad, flat horseshoe-shaped area over the nostrils, a horn-like projection above, and a shorter, rounded projection in between, the noseleaf's function is to emit echolocation calls for orientation and hunting. The ears are large and black, and the eyes extremely small, dwarfed by the noseleaf. The natural fur colour is dark brown, but this bat's habit of roosting in caves can lead to chemical bleaching, leaving the fur orange (2).

Found in Thailand, Peninsular Malaysia, Sumatra, Java (3), Vietnam (4), Burma (5) and Laos (2).

The lesser brown horseshoe bat is found in primary rainforest, where it feeds at all levels beneath the lower canopy. It roosts in large numbers in caves and in smaller numbers in cracks between rocks. It is often found roosting with its close relative, Blyth's horseshoe bat (Rhinolophus lepidus) (2).

This species feeds on insects, hunting at night using echolocation to locate prey items and move amongst the dense jungle vegetation. It calls at a constant ultrasonic frequency of 86 kHz, enabling it to detect the flutter of an insect's wings (2).

The majority of pregnant females of the lesser brown horseshoe bat are found between February and April, and are with young pups between May and July. A single pup is born to each female, who cares for it for up to a year. At birth it weighs a massive one quarter of its mother's weight, and she may continue to carry it on feeding flights for two months (2).

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 (7).

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