Early Postnatal Growth and the Development of Temperature Regulation in the Mongolian Gerbil, Meriones unguiculatus

Abstract

The growth and development of young in 22 litters of Mongolian gerbils, Meriones unguiculatus, were studied for a period of 4 weeks after birth. Data on body weight and on total, body, tail, hind foot, and ear length are given. The early development of the pelage, ears, eyes, teeth, and general behavior are correlated with the development of temperature regulation, as studied in 10 litters. From birth to about day 13 the neonate gerbil is essentially ectothermic. Between days 13 and 14 and weaning, which occurs about day 21, there is a rapid development of endothermy. The latter period is also characterized by the eruption of teeth, opening of the eyes, rapid development of the pelage and hearing, development of grooming patterns, first attempts to eat solid food, and first forays from the nest. Early growth and development of M. unguiculatus is accelerated and similar to that of several other small cricetid rodents.