Breeding in wild populations of the Red Kangaroo, Megaleia rufa

Abstract

The study was based on the examination of 3342 kangaroos collected at' three sites in inland New South Wales and Queensland, that were chosen to give a series of different environments. Some female red kangaroos in the wild reached sexual maturity before they were 18 months old, but most did not do so until they were about 30 months old. There were considerable differences in the age at which sexual maturity was reached according to the aridity of the region. Male red kangaroos in the wild reached sexual maturity at 28-39 months of age but this age also might have been modified by the environment from time to time and fxom place to place. Of the 2528 mature females examined 78.7% had pouch young and 21.5% of the females with pouch young also had a young-at-foot. There was some intrauterine mortality but the principal mortality occurred at the end of pouch life, from 196 days of age onwards and among the young-at-foot. The mortality was greatest in the area of drought where 83 % failed to reach maturity. The red kangaroo bred continuously throughout the year and it is concluded that mortality of pouch young, probably induced by failure of lactation, consequent on the mother's reduced food supply, was an important factor in the regulation of numbers.