Horsefield's Fruit Bat (Cynopterus horsfieldi)
Horsfield's fruit bat is a medium-sized megabat, intermediate in size between flying foxes and pygmy fruit bats. Adults weigh around 55 to 60 grams (1.9 to 2.1 oz), and have light grey to brown fur, with a reddish brown or orange mantle around the shoulders. In some males the mantle extends across the chest, and the fur is often brighter in colour than in females. The rim of the ears and the skin overlying the metacarpals and phalanges within the wing are white. Juveniles have a more bland coat pattern, with uniformly dull buff or grey fur. The bats have a short, broad snout, ending in a pair of almost tubular nostrils. Both the eyes and ears are large, although the latter have a simpler structure than in most other bats, and lack a tragus. The wings have a low aspect ratio and high wing loading, typical of many mega bats, and indicating a relatively slow flight speed and moderate manoeuvrability. It is named for Thomas Horsfield, an American naturalist who presented the type specimen to the British Museum.
Distribution and Habitat
Horsfield's fruit bat is found in Thailand, Indonesia, Malaysia, and Brunei. Within this region, it inhabits a broad range of lowland habitats, from dense primary rain forest to agricultural land and suburban gardens. Range Description: This species is found in Thailand, Cambodia, Malaysia, Borneo, Java, Sumatra, Lesser Sunda Islands, and adjacent small islands in Indonesia. It has also been recorded from Bali, Lombok, Simelue and Nias (I. Maryanto pers. comm.).
Indonesia; Malaysia; Thailand
There are four recognised subspecies:
Cynopterus horsfieldii horsfieldii - Java and islands East to Sumbawa
Cynopterus horsfieldii harpax - Thailand, peninsular Malaysia, Sumatra
Cynopterus horsfieldii persimilis - Borneo
Cynopterus horsfieldii princeps - Nias
This species is common in Indonesia (I. Maryanto pers. comm.),
but locally rare in northern and Western Thailand
(S. Bumrungsri pers. comm.).
Population Trend: Unknown
Biology and Behaviour
Horsfield's fruit bats eat the fruit of strangler figs, Elaeocarpus, and Payena, and the flowers of bitter beans. They have been reported to pluck fruit from trees and carry it to roosts elsewhere in order to feed. During the dry season, hen fruit is in short supply, they instead feeds on pollen, which they take from a wide variety of different plants. It is found in many habitats in Indonesia but only pristine forests in Thailand. In Malaysia it has been found in agricultural areas, suburban parks, fruit orchards and secondary forest as well as good forest (Campbell and Kunst, 2006). They have a harem social structure, and are highly gregarious when roosting in caves, but are found in smaller groups when roosting in forests. It makes tent roosts.
They live in small groups, consisting of a single adult male and up to five females and their young. Although these groups are maintained year round, individual females often move between different groups, and may spend some time nesting alone between leaving one group and joining another. They roost in trees and cave mouths, reportedly favouring banana trees. They often modify their roosting sites by constructing tents from the leaves, partly cutting through them to make an inverted "V" shape. They breed throughout the year, but most commonly give birth at two times of the year: between February and March and between July and August. They have been reported to live for at least 31 months.
There are no major threats to this species throughout its
range. Deforestation is a threat in Thailand, but elsewhere this species adapts
to disturbed habitats.
Isolated populations from Thailand need to be examined taxonomically (S. Bumrungsri pers. comm.). It is found in a number of protected areas throughout its range.