Reproduction, Growth and Survival of Young in the Mountain Possum, Trichosurus Caninus (Marsupialia)

Abstract

The biology of T. caninus was examined in the field and in captivity over a 4-year period. The season of parturitions is restricted, with more than 87% of births between February and May. The sex ratio of the pouch young did not differ from parity and there was no significant difference between frequency of suckling of right or left teat, alternate teats being used during successive lactations. Measurements of 10 known-age individuals showed that head length (y) had a linear relationship to age (t) up to 210 days (regression, t = 2.917y - 19.355). Ear length and pes length were not linearly related to age. The young emerge from the pouch 175-200 days after birth, remain physically dependent on their mothers for the next 2-3 months and are weaned at > 240 days. Individuals in the field could be assigned to 1-year-old, 2-year-old or adult categories by a combination of head length, body weight and condition of external reproductive organs. Females may mature at 2 years old, although only 50% produce young at this age. The testis approximates adult size in the latter half of their third year. Survival of the dependent young is low, only 51.8% and 37.9% reaching 175 days and 1 year old respectively.