POSTNATAL-GROWTH AND DEVELOPMENT OF THE HAIRY-FOOTED GERBIL, GERBILLURUS-PAEBA-EXILIS

The growth and development of six litters (21 pups) of captive Gerbillurus paeba exilis are described. Growth is slow with mean adult mass (32,4 g) being reached after 102 days, although the youngest sexually mature male and female were 63 days and 84 days old respectively. Physical development is also comparatively slow and weaning is completed after 30 days. Mass, tail length and hindfoot measurements were subject to much less error than head/body length data. Mass values of wild and captive gerbils are compared where possible. Two 'critical periods' in development were pin-pointed, i.e., (i) Day 12, when all the motor abilities developed rapidly, and (ii) Day 17, when the eyes opened and social behaviour followed. Behavioural development was divided into four periods: neonatal, transitional, socializing and juvenile.