Description / Behavior: A series of 27 specimens from northeastern Luzon averaged 75.3 mm in total length and 52.1 mm in forearm length (Mudar and Allen 1986). A series of 15 specimens from Negros averaged 17.9 grams in weight (Heaney, Heideman, and Mudar 1981). There is no tail. The thumb is long, about 25 mm in length, and the hind foot is short, about 13 mm in length. The coloration is given by the describer as "cinnamon brown" on the back, pale "mummy brown" in the shoulder region, darker in the head region, and "wood brown" beneath, with a slight tinge of silver along the midline of the belly.

None of the other genera similar to Cynopterus has such a relatively long thumb. One pair of incisors, one pair of canines, and four pairs of premolars and molars also set Haplonycteris apart from related genera. The describer stated: "Haplonycteris belongs in the group of small bats that resemble Cynopterus in which the postorbital foramen has become obliterated. In the reduction of the tooth formula with the strengthening of the remaining teeth, it appears to be the most highly evolved of this group. The unusually developed cusps and transverse ridges also indicate a greater degree of differentiation" (Lawrence 1939).

Mudar and Allen (1986) found Haplonycteris to exhibit a marked preference for forest habitat and often to be the only bat caught in nets set away from water or agricultural fields. Heideman (1988) reported that this bat has an annual reproductive pattern that seems associated with seasonal patterns of abundance of the fruit upon which it feeds. Births are highly synchronous within a given population, occurring in May or June on Negros Island but up to 3 months later in other areas. Although mating may occur throughout the year, synchronization of births is achieved by a postimplantation delay in embryonic development. Females also undergo a postpartum estrus 1-3 weeks after giving birth, and most become pregnant at this time. The period of delay lasts up to 8 months and is followed (starting about March on Negros) by 3 months of rapid embryonic growth. A single young is born, and lactation lasts about 10 weeks. Most females that are born in June on Negros become pregnant themselves in October or November, at 5 or 6 months. It eats ripe fruit of pepper plants, figs, wild bananas and other forest palnts. It is very long lived and can reach up to 12 years of age. Small groupd of related females live together with a single unrelated adult male.
Interesting Information: It's the smallest bat in the world
Comments: Genetic variation was studied by Peterson and Heaney (1993) and reproductive biology by Heideman (1989)

Photograph Information: Courtesy of  Paul Heideman