Lesser Brown Horseshoe Bat

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). In Peninsular Malaysia, the majority of pregnant females of the lesser brown horseshoe bat have been 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).

Deforestation for agriculture, particularly for oil palm plantations in recent years in Malaysia, Indonesia and Thailand, is an issue of major concern for many forest-dwelling species, even within so-called protected areas. Regarding oil palm, some companies and large retailers have agreed to source palm oil from sustainable sources via a certification process developed by the Roundtable for Sustainable Palm Oil. The principal criterion relevant to biodiversity is that new plantations have not been established on land of High Conservation Value (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 (8).

As a medium-sized member of the horseshoe bat family, this species is characterised by its complex noseleaf. The noseleaf consists of a broad, flat horseshoe-shaped area over the nostrils, a horn-like projection above, and a shorter, rounded projection in between. The function of the noseleaf 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).

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).

The lesser brown horseshoe bat is found in Thailand, Peninsular Malaysia, Sumatra, Java (3), Vietnam (4), Burma (5) and Laos (2).

Classified as Lower Risk / Least Concern (LR/lc) on the IUCN Red List (1).

The main threat to local lesser brown horseshoe bat populations is the disturbance of cave roosts, caused by mining activities or the collection of guano and bird nests. A wider threat, relevant to most bat species in Southeast Asia, is from habitat loss. The rapid increase in land devoted to commodity agriculture (such as cocoa, coffee, oil palm, rice and rubber) has resulted in extensive loss of forest in the last 20 years. In recent years, one of the largest agricultural drivers of deforestation in Malaysia, Sumatra and Thailand has been oil palm. Together, Malaysia and Indonesia export 88 percent of the world's palm oil, for use in products such as margarine, lipstick and detergent. In addition, despite the contribution of many bats in the control of insect crop pests, persecution of bats is also a threat (6) (7).

The lesser brown horseshoe bat (Rhinolophus stheno) is a species of bat in the family Rhinolophidae. It is found in Indonesia, Laos, Malaysia, Thailand, and Vietnam.