Postnatal growth and age estimation in the Indian false vampire bat (Megaderma lyra)

Abstract

The Indian false vampire bat Megaderma lyra produces a single young under captive conditions, which is altricial at birth. Empirical growth curves were derived by measuring length of forearm, body mass and length of the total gap of the fourth metacarpal–phalangeal joint. Length of forearm and body mass followed a linear pattern of growth until day 28 and subsequently reached stability. The length of the total gap of the metacarpal–phalangeal joint initially showed a linear increase up to 4 days, followed by a linear decrease until 34 days when it closed. A quantitative method of estimation of age was derived from values of length of forearm and length of the total gap of the fourth metacarpal–phalangeal joint during the preflight (first 28 days) and postflight stages, respectively. Width of the 95% confidence level was ± 1.2 days at a mean length of forearm of 51.6 mm, and ± 0.07 days at a mean length of the total gap of the fourth metacarpal–phalangeal joint of 1.89 mm. Initiation of flight occurred 24 days after birth. At 28 days of age, young were able to forage on their own. There was no significant difference in the growth pattern of young held in captivity compared to that of young grown under natural conditions.