The Greater Short- nosed
Fruit Bat or Short-nosed Indian Fruit Bat (Cynopterus sphinx) is a
species of bat in the Pteropodidae family. It is found in Bangladesh,
Bhutan, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar,
Philippines, Sri Lanka, Thailand, and Vietnam.
These bats have a relatively long snout. Their upper parts are brown
to grey-brown with paler under parts. The fur is very fine and silky.
The ears and wing bones of C.sphinx are edged in white. Lower cheek
teeth rounded without accessory cusps. The wing span of the adult is
about 48 cm. Juveniles are lighter than adults. Average forearm length
70.2mm (64-79mm) (Bates & Harrison,1997).
C.sphinx is common found in tropical forests and areas where fruit
crops are cultivated. They can also be found in grassland and mangrove
forests. They typically nest high in palm trees. The bats chew the
fronds of the palms to construct fairly simple tents. These bats are
also known to construct tents by closely interweaving the leaves and
twigs of creeping vines which cover buildings, but such nests are
constructed only when palms are not available.
The species is gregarious, and typically roots in same sex groups of
8-9 individuals. The sexes remain separate until the mating season, when
group size increases. It is usual for 6-10 males and 10-15 females to
share palm frond tents during the breeding season. Males stay with
females for some time after mating, but later return to same sex groups.
The adult sex ratio is very female biased. Researchers attribute this to
the relatively rapid maturation of females compared to males. In Central
India, C. sphinx breeds twice per year. Females produce a single young
at a time. The function of the female reproductive system is interesting
in that each half of the bicornate uterus functions during alternate
breeding cycles. The first pregnancy cycle occurs from October through
February/March. Mating occurs immediately postpartum, and a second
offspring is born in July. Gestation period is about 3-5 months. In 72%
of bats, the first pregnancy occurs in the right horn of the uterus. The
corpus luteum in the right ovary persists for some time after the
pregnancy and prevents ovulation from occurring in the right ovary
during the second breeding cycle. This creates the pattern of alternate
functioning of the two horns of the uterus. However, the corpus luteum
in the left ovary does not persist until the beginning of the next
breeding cycle. As yet, no reason has been found for the dominance of
the right horn during the first breeding cycle. Newborn bats weigh about
13.5 g and have a wingspan of 24 cm. By the time of weaning at 4 weeks
of age, young bats weigh 25 g and have wings spanning 36 cm. Female
short-nosed fruit bats reach sexual maturity at 5-6 months of age, but
males are not capable of breeding until they are a year old.
These bats are frugivorous, locate their preferred food items by
scent. They have been described as voracious feeders, eating more than
their body weight in food in one sitting. Some preferred fruits include
ripe guava, banana, chikus (a popular Indian fruit crop), dates and
liches.
Short-nosed fruit bats inflict serious damage on many fruit crops,
and as a pest species. In addition, these bats are possible vectors for
Japanese encephalitis, which is very serious disease in humans. These
bats are important dispersers of date palm seeds, and pollinate many
night blooming flowers. |
