We studied the in¯uence of moonlight upon the foraging activity pattern of the fruit bat Cynopterus sphinx. We observed the bats when foraging on the fruits of Calophyllum inophyllum and on the leaves of Mimusops elengi and Cassia ®stula for 31, 27 and 28 days, respectively at the botanical garden in the Madurai Kamaraj University campus. The number of feeding bouts was recorded every hour between 18:00 and 05:00. A feeding bout involves a bat landing on the tree and collecting a part (or whole) of the fruit or a leaf. The total number of feeding bouts was negatively correlated with per cent moonlight each night. The number of feeding bouts decreased during the waxing phases of the moon. During the period of new moon the mean number of feeding bouts was signi®cantly higher compared to the periods of other phases. During the ®rst quarter and the last quarter phases, feeding occurred more during the dark part of the night, especially when the bats foraged upon M. elengi and C. ®stula. While cloud cover enhanced the foraging activity, lightning and thunder suppressed it. Our study indicates that moonlight in¯uences the foraging activity of C. sphinx.

This study documents the postnatal growth, age estimation and development of the foraging behaviour of the fulvous fruit bat Rousettus leschenaulti under captive conditions. At birth, the young were naked and pink with closed eyes and folded pinnae. By day four of age, their eyes had opened and the pups began to move. The mean length of forearm in 5-day-old pups was 24.9 mm and body mass was 10.8 g, equivalent to 32.3% and 14.2% of the values from postpartum females. The length of forearm and body mass increased linearly until 45 and 50 days, respectively, and thereafter maintained an apparent stability. The epiphyseal gap of the fourth metacarpal-phalangeal joint increased until 15 days, then decreased linearly until 75 days and thereafter closed. Age was estimated quantitatively, based on linear changes observed in the length of the forearm and epiphyseal gap. Pups began to roost separately, but adjacent to their mothers when 30 days old and flew clumsily when they were about 40 days old. After attaining clumsy flight, the young bats made independent foraging attempts feebly by biting and licking small fruit pieces. Young bats were engaged in suckling as well as ingesting fruits when they were about 50 days old. Between 55 and 65 days, they flew well and fed on fruits. At the age of 75 days, the young bats were completely weaned and at two months, their foraging behaviour was similar to that of their mothers. There was no significant difference in the growth pattern of the young maintained in captivity compared with those under natural conditions.

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The short-nosed fruit bat, Cynopterus sphinx, begins to visit fruit-bearing trees about 30 min after sunset. Individual bats often hover near or land on fruits or on nearby branches to remove whole or parts of fruits with their mouth. These bats seldom remain in the fruit-bearing trees to feed, but instead carry fruits to feeding roosts, repeating this behaviour several times throughout the night. Analysis of the temporal distribution of feeding behaviour has revealed two peaks of activity, one in the pre-midnight hours when bats fed mostly on ‘steady state’ fruits, and another during the post-midnight hours when bats fed on ‘big-bang’ fruits. Only solitary bats visited and fed on species with steady state fruiting phenologies, whereas groups of bats regularly visited and fed on species with big-bang fruiting phenologies. Thus, plant species which produce large numbers of fruits appear to promote group foraging during the latter hours of the night. It is suggested that the temporal use of available fruits in south India made it possible for C. sphinx to successfully exploit them, and thereby reduced interference competition with conspecifics.