Behaviour of Red Kangaroos, Macropus rufus (Desmarest, 1822) (Macropodidae; Marsupialia) in northwestern New South Wales, Australia

Abstract

About 1500 man-hours were spent in the field, studying the behaviour of the Red Kangaroo (Macropus rufus) in a semi-arid habitat in northwestern N.S.W., Australia. The population was divided into six age/sex classes: large and medium-sized adult males, adult females. sub-adult males and females, and dependent young. Individual activities, grouping patterns, non-agonistic, agonistic and sexual interactions of these age/sex classes were studied. During daylight, Red Kangaroos are most active in the few hours following dawn and preceding dusk. Most of the diurnal time budget of Red Kangaroos was spent resting and feeding with social behaviour forming a small proportion of the day's activities. Red Kangaroos form small groups (mean 2.2 animals) which are impermanent, varying frequent ly in size and composition. The nonagonistic behaviour of Red Kangaroos may be important in sexual and/or individual recognition. Large males most frequently initiated and performed such behaviour. Mothers and young also frequently interacted with non-agonistic behaviour, some of which (e.g. allo-grooming, social play) was exclusive to this dyad. Agonistic behaviour included supplanting interactions and fighting. Size relationships determined the success in supplanting interactions, the larger animal usually winning. Most supplanting interactions occurred in competition for favourable lying up sites; and, in male-male interactions, for females. Success in the ritualized fights ("boxing") of male Red Kangaroos depends on greater strength in pushing and wrestling and may establish dominance relationships between males. Most sexual behaviour was performed by large adult males. The existence of brief one-to-one consort relationships between a large male and oestrus female is suggested. Maternal care and communicatory behaviour of Red Kangaroos are also briefly discussed. The social organization of Red Kangaroos reflects the influences of low predation pressure, nomadism, a brief oestrus, no synchronized breeding period, and unpredictable productivity in an arid environment.