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Postnatal growth, age estimation and development of foraging behaviour in the fulvous fruit bat Rousettus
V Elangovan1, H Raghuram, E Yuvana Satya Priya
1Department of Animal Behaviour and Physiology, School of Biological Sciences, Madurai Kamaraj University, Madurai 625 021, India.
Insights
This study details the growth and foraging development of young fulvous fruit bats (Rousettus leschenaulti) in captivity. Captive-raised bats showed similar growth and behavioral development to wild counterparts.
Area of Science:
- Chiropterology
- Mammalogy
- Developmental Biology
Background:
- Understanding the early life stages of bats is crucial for conservation efforts.
- The fulvous fruit bat (Rousettus leschenaulti) is a significant seed disperser in its ecosystem.
- Limited data exists on the detailed postnatal development of Rousettus leschenaulti under controlled conditions.
Purpose of the Study:
- To document the postnatal growth trajectory of Rousettus leschenaulti in captivity.
- To establish methods for age estimation in young bats based on physical development.
- To observe and describe the development of foraging behavior from infancy to independence.
Main Methods:
- Captive rearing of Rousettus leschenaulti pups from birth.
- Regular measurements of body mass and forearm length.
- Assessment of epiphyseal gap closure in the fourth metacarpal-phalangeal joint for age estimation.
- Behavioral observations of roosting, flight, and feeding patterns.
Main Results:
- Newborn bats were naked with closed eyes; eyes opened by day four.
- Forearm length and body mass increased linearly until 45-50 days, then stabilized.
- Epiphyseal gap closure provided a quantitative method for age estimation, closing by 75 days.
- Independent foraging and adult-like feeding behaviors were observed around two months of age.
- Growth patterns in captivity mirrored those observed in natural conditions.
Conclusions:
- Postnatal development, including growth and foraging, in captive fulvous fruit bats is comparable to wild populations.
- Forearm length and epiphyseal gap provide reliable indicators for estimating the age of young bats.
- The study provides valuable baseline data for understanding bat development and informing conservation strategies.
Abstract:
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.
