Postnatal growth in the Lesser Mouse-eared bat, Myotis blythii, in captivity

Abstract

Postnatal growth of body mass, forearm and the epiphyseal phalangeal gap was studied in three Lesser Mouse-eared bats, Myotis blythii, which were born and reared in a flight cage. The pups at birth had a mean birth body mass of 7.4 g and forearm length of 26.0 mm. At 64 days, mean body mass had reached 94.4% of adult mass (29.3 g) and mean forearm length was 96.1% of adult length (58.6 mm). The length of forearm and body mass increased linearly during the first 3 weeks, and thereafter maintained an apparent stability. The epiphyseal gap of the fourth metacarpal-phalangeal joint increased until 16 days, then decreased linearly until 52 days and thereafter fused. The rate of body mass gain and forearm growth during the first 24 days was 0.8 g/day and 1.32 mm/day respectively. Both asymptotic size of body mass and forearm together with the growth rate of body mass were higher in the captive bats. However, the growth rate of forearm and the rate of closure of the epiphyseal gap in the free-living population were slightly less than in the captive individuals.