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

[摘要] Groups of translocated orphaned juvenile African elephants were studied in holding pens andfollowing 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 allgroups allomothering was observed to some degree. One 5 year old female prematurelyassumed the role of leader and this role appears to be learned. Most groups established a lineardominance hierarchy.Placing the trunk tip into a partner's mouth correlated with play-fighting and aggression. Thisbehaviour is suggested to be one of appeasement to reduce aggressive motivation and preventescalation thereof, and that the behaviour is ritualised. Four possible evolutionary steps arepresented.Nearest Neighbour analyses illustrated the changing social positions of some juveniles relative toother individuals. Tight grouping was assumed to indicate insecurity. There was a markeddifference in behaviour pattern during resting times. Groups without adults were within touchingdistance of one another whilst resting. In a group containing an adult female some juvenilesdispersed more and some juveniles formed a subgroup. It appears that dominance hierarchies,individual social relationships and caretaking of young were important factors which affectedgroup cohesion and could influence a more central position within a group.Certain behaviour patterns were defined as being stress related and compared among thegroups. There was a significant decrease in arousal behaviour after the introduction of an adultfemale. Aggressive behaviour was the most frequent behaviour in four groups whilst pennedand following their release. Play behaviour was absent in three penned groups, and tended togradually increase following the release. Temporal gland secretion occurred during excitement,anticipation and nervousness. Secretion occurred in all age and sex classes. Females tend tosecrete more frequently than males and older individuals more than younger ones.Frustrated or stressed animals vocalized more frequently than relaxed ones, as did calves below2 years of age who tended to use louder calls, than older juveniles. Acoustical analyses of fourvocalizations are presented. Very young individuals appear to vocalize using marginally higherfrequencies.

[发布机构] University of Pretoria