The influence of food on breeding in the Red Kangaroo in Central Australia

Abstract

The percentage of adult female red kangaroos, Megaleia rufa (Desm.), in breeding condition, the abundance of food, the abundance of kangaroos, and the severity of the weather, were estimated every six weeks or so from January 1961 to October 1962 on an open plain 30 miles north of Alice Springs. In that time, 578 kangaroos were shot and examined, the herbage eaten by kangaroos averaged 6.7% of the basal length of transects measured, an average of 1.6 kangaroos were seen per mile travelled, and drought prevailed for about half the time. Breeding in kangaroos depended mainly on the abundance of food, which in turn depended on the weather. The density of kangaroos had no measurable influence on breeding or on the supply of food. The quality as well as the quantity of food may be important to kangaroos not only in maintaining breeding but in rapidly initiating it after droughts break. The particular qualities of the food responsible are unknown. It is suggested that the quality maintaining breeding might be the protein content, and that the quality initiating it might be oestrogenic substances in freshly sprouting native pastures.