Locally known as Horsfield’s fruit bat, Larger Dog-faced Fruit Bat or Cecadu Pisang Besar in Malay, Cynopterus horsfieldii is a medium-sized plant-visiting bat belonging to the family Pteropodidae (Tan et al., 1999). This species was named after an American physician and naturalist, Dr. Thomas Horsfield (1773–1859), who made extensive collections of plants and animals while working in Java for the Dutch East India Company.
Generally, fruit bats have a typically dog-like face with large eyes, and simple and relatively small ears. Their wings are usually broad and mostly without fur. In addition to these features, C. horsfieldii has grey-brown upperparts, slightly yellowish-brown underparts, and a dark reddish-brown collar in adult males which is paler in females (Francis, 2008). The immature bat has dull buff or grey fur. The edges of the ears and outline of the wing-bones are white in colour. Cynopterus horsfieldii has broader and squarer cheek teeth than other Cynopterus bats, with distinct cusps or ridges on the lower premolar and first lower molar. Its larger body size with an average mass of 57.9 g, distinguishes it from C. sphinx (Greater Short-nosed Fruit Bat) which is smaller and has more rounded cheek teeth (Francis, 2008).
Together with C. brachyotis (Lesser Short-nosed Fruit Bat), C. horsfieldii is also known as the most common and abundant species in Peninsular Malaysia (Hasan et al., 2012; Jayaraj et al., 2012). In mainland South-East Asia, it is distributed in Vietnam, Laos, Cambodia, Thailand and Peninsular Malaysia. It is also found in Borneo, Sumatra, Java and the adjacent islands (Francis, 2008). This bat can be found in a wide range of elevations ranging from mangrove forest and the lowlands to the hills, sub-montane and montane forests. Medway (1983) and Hodgkison et al. (2004) also stated that these bats are commonly found in oil palm plantations, orchards and open areas.
According to Payne et al. (1985), C. horsfieldii roost mainly in rock shelters or caves and occasionally in trees or palms. It has also been found roosting in or under banana leaves (Musaceae), which were modified into an inverted ‘V-shaped’ structure which the bat made by biting the midrib of the leaf midway between base and tip (Campbell & Kunz, 2006). This bat has a polygynous mating system, with a harem-based social structure which consists of one adult male and up to five adult females and their offspring (Tan et al., 1999; Campbell et al., 2006).
Cynopterus horsfieldii is a predominantly frugivorous bat, but leaves, flowers and nectar are also in its diet. It also tends to feed on larger fruit than other Cynopterus species (Francis, 2008). This species has been reported to feed on the fruits of Mangifera indica (Mickleburgh et al., 1992), strangler figs (Ficus spp.), Elaeocarpus stipularis, and Payena lucida, and flowers of Parkia speciosa (Campbell et al., 2006). When fruit is scarce, especially during the dry season, it feeds on pollen taken from a wide variety of plants (Campbell & Kunz, 2006). Because of its wide diet, it plays an essential role as pollinator for fruit tree species as well as seed dispersal agent for forest regeneration (Mickleburgh et al., 1992).
Cynopterus horsfieldii is categorized as least concern (LC) by the IUCN Red List of Threatened Species (Bates et al., 2019). Although no major threats to this species have been reported, deforestation and habitat loss will decrease its population numbers, which thereby will affect fruit production in the future.