Growth and development of the brush-tailed rabbit-rat (

Abstract

Knowledge of life history can reveal much about phylogeny, behaviour and ecology, all of which are essential for managing threatened species. Conilurus penicillatus has declined over its range and there is little information on its biology, including growth and development. Weight and four body measurements were recorded using 87 progeny of Mitchell Plateau stock, from birth to >150 days. Developmental features were recorded in animals less than 3 months old. Morgan–Mercer–Flodin, 4-Parameter Richards and Exponential growth models were applied to metric data. Neonatal development was rapid (pinnae were unfolded at birth, ears opened at 7–10 days, eyes opened at 11–14 days). An almost-complete juvenile pelage developed by 14 days. Weaning occurred at 23–40 days and adult size was attained by 100 days. At birth, males were significantly heavier than females but this difference was not evident in adults (mean = 168 g, combined sexes), when only head length was greater. Lack of sexual size dimorphism may be associated with a monogamous social structure. Conilurus penicillatus is more precocial but grows more slowly than the closely related Mesembriomys gouldii. Variation in growth and development strategies among tree-rats may be related to differences in diet, habitat and other life-history characteristics.