The development of social behaviour in translocated juvenile African elephants Loxodonta africana (Biumenbach)

Abstract

Groups of translocated orphaned juvenile African elephants were studied in holding pens and following their release to assess how they re-organize and restructure socially by adopting roles, and if they show behavioural signs of stress. An adult female adopted a young individual. In all groups allomothering was observed to some degree. One 5 year old female prematurely assumed the role of leader and this role appears to be learned. Most groups established a linear dominance hierarchy. Placing the trunk tip into a partner's mouth correlated with play-fighting and aggression. This behaviour is suggested to be one of appeasement to reduce aggressive motivation and prevent escalation thereof, and that the behaviour is ritualised. Four possible evolutionary steps are presented. Nearest Neighbour analyses illustrated the changing social positions of some juveniles relative to other individuals. Tight grouping was assumed to indicate insecurity. There was a marked difference in behaviour pattern during resting times. Groups without adults were within touching distance of one another whilst resting. In a group containing an adult female some juveniles dispersed more and some juveniles formed a subgroup. It appears that dominance hierarchies, individual social relationships and caretaking of young were important factors which affected group cohesion and could influence a more central position within a group. Certain behaviour patterns were defined as being stress related and compared among the groups. There was a significant decrease in arousal behaviour after the introduction of an adult female. Aggressive behaviour was the most frequent behaviour in four groups whilst penned and following their release. Play behaviour was absent in three penned groups, and tended to gradually increase following the release. Temporal gland secretion occurred during excitement, anticipation and nervousness. Secretion occurred in all age and sex classes. Females tend to secrete more frequently than males and older individuals more than younger ones. Frustrated or stressed animals vocalized more frequently than relaxed ones, as did calves below 2 years of age who tended to use louder calls, than older juveniles. Acoustical analyses of four vocalizations are presented. Very young individuals appear to vocalize using marginally higher frequencies.