Growth and development of the Murid Pseudomys novaehollandiae

Abstract

Growth of the hind foot, head and weight were studied from birth to 150 days of age in a captive colony of P. novaaehollandiae, and development of external body features was recorded from birth to weaning. The altricial young were sparsely haired and blind at birth and a juvenile pelage was present by about 10 days. The eyes opened at 15 (13-19) days and the young were weaned during the fourth week. Instantaneous relative growth rates showed that growth (weight) during the first 40 days was multiphasic and that the growth rate changed considerably at both the opening of the eyes and weaning. The relationships of seven body measurements (head and body, head, ear, foreleg, hind leg, hind foot and tail) were compared to a linear equivalence of weight; all showed a sigmoidal relationship except that of head and body, which was a straight line. Hind foot and head length measurements of growing animals reached 90% of adult size at about 26 days, and weight at about 85 days. In Australian murids, one group grows relatively quickly and another grows slowly.