Growth of an Australian Murid (Pseudomys novaehollandiae) in the Wild

were live-trapped for dissection (1972—74) and capture-mark-release (1974—76) studies in central coastal New South Wales, Australia. Body-weights of single and multiple capture animals less than 1 year old are used to describe growth under natural conditions. Variations in growth ra te are related to (1) time of birth within the breeding season (early-or late-born cohorts) and (2) rate of sexual development (mature or im-mature during the season of birth). Animals which matured grew more quickly than those which remained immature until the following season. As a group, mature individuals reached a higher asymptotic weight (16.4 g) than immature individuals (14.9 g) and attained 90 % of this asymptote at a younger age (60 days compared to 75 days). Individual growth records showed that this difference in growth ra te only became apparent af ter 50 days of age. Although the early-born cohort grew more rapidly than the late-born, the difference was minimal if mature animals were excluded from the analysis. Final body weight and overall growth pat tern were similar under field and laboratory conditions except that laboratory animals weighed more when under 30 days of age