Postnatal growth, age estimation and development of foraging behaviour in the fulvous fruit bat Rousettus leschenaulti

This study documents the postnatal growth, age estimation and development of the foraging behaviour of the fulvous fruit batRousettus 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

Wing morphology and flight performance in Rousettus leschenaulti

We studied development of wings of Leschenault's rousette, Rousettus leschenaulti. Wingspan and wing area grows linearly until 45 days of age. Young bats begin to flutter at 45 days, manage sustained flight at 60 days, and achieve independent foraging flight at 75 days. Aspect ratio varies until 15 days, and adult proportions are attained at 2 months. Wing loading decreases linearly until 50 days and thereafter increases slowly, possibly because of completion of growth of wing area. Wingspan growth fits a logistic model, whereas wing area growth fits a Gompertz model. Minimum predicted flight power (Pmp) and maximum range power (Pmr) begin to increase linearly after remaining relatively constant for 30 days. At 150 days both are nearly equal to 65% of the power requirements of postpartum females. The predicted minimum power speed (Vmp), maximum range speed (Vmr), and minimum theoretical radius of a banked turn (rmin) decrease for 40 days, thereafter increase linearly, and at 150 days all are close to 90% of the respective values of the postpartum females