All Bats

Order: CHIROPTERA

Bats are distinguished from all other mammals by their wings and their ability to fly. Two other groups of Bornean mammals - the colugo and the flying squirrels - have developed the ability to glide long distances, but they are not capable of true flight. They have gliding membranes between their legs, quite different from the wings of bats which are formed from elongate fingers on the hands. Flying bats are often confused with birds but can be easily distinguished with practice by the shape of their wings and the pattern of flight.

Bats are difficult to identify unless they can be captured and examined closely. In the hand, most species can be distinguished based on easily visible characters and measurements, but some features such as coloration are rather variable and it is sometimes necessary to examine the skull or dentition for confirmation. With care the teeth can usually be examined in a live bat by gently opening the mouth with a toothpick or similar tool. A small magnifying glass is helpful to see the details. The skull can only be properly examined in a museum specimen, but many features of skull shape are reflected in the outward appearance of the head.

Bats have been very little studied in Borneo, and it is likely that additional species occur in the area. For the benefit of scientists who wish to confirm their identifications or who may have caught species not in this book, technical descriptions of each genus are provided, together with diagrams of most of the skull types. To make the species descriptions as readable as possible, these technical characters are mainly confined to separate sections at the start of each genus.

Care must be taken when identifying bats not to confuse immatures with adults. Immatures are generally much duller in colour, grey or grey-brown. If held against a bright light, the wing joints of immatures appear banded where the cartilage has not yet turned to bone (the adult joint looks like a solid lump).

The Bornean species of bats are classified into 8 families, which can be distinguished based on ear shape, muzzle shape, the presence or absence of a noseleaf and the tail pattern.

Large Flying Fox (Pteropus vampyrus)

Measurements: FA 185-200, T none, Wt 645-1100 (5 Malayan specimens)

Identification: Largest Bornean bat. Back black with grey streaking; back of head and neck orange-brown; rest of head and underparts blackish brown. Immatures uniform dull grey-brown.

Similar species: the Island Flying Fox, P.hypomelanus, is much smaller, with different coloration.

Ecology and Habitat: Roosts in large established colonies on open branches of trees, often in mangrove or nipah palm, sometimes flies long distances to feed on flowering or fruiting trees. Eats both nectar and fruit including some orchard species such as rambutans and mangoes. Pollinates the flowers of many forest trees including durians.

Distribution: P.v.natunae. Found throughout lowland coastal areas, occasionally invading the interior during the fruiting season.

Pouched Tomb Bat (Taphozous saccolaimus)

Measurements: FA 71-78, T 33-34, E 19-21, Wt 40-50 (5 specimens).

Identification: Upperparts blackish brown variably marked with white. Underparts usually white, but in one colour phase, dark brown. Metacarpal pouch (at the wrist) poorly developed. Has a distinct glandular pouch under the chin. Legs and feet hairless. All Tomb bats, Tapohozous spp., can be recognized in flight by their long, narrow, translucent whitish wings and the audible clicks of their echolocation calls. This is the largest species with the whitest wings.

Similar Species: other tomb bats, Taphozous spp., are smaller, have a well developed metacarpal pouch and fur on the legs.

Ecology and Habitat: Sometimes found in houses in colonies varying from a few individuals to a few hundred. Also roosts in hollow trees and rock crevices.

Distribution. T.s. saccolaimus. Recorded from Samunsam, Kuching and environs in Sarawak.