Social determinants of movements and aggregation among free ranging elephants (loxodonta africana, blumenbach) in amboseli, Kenya

Abstract

It is now widely accepted that elephant female groups live in complex social units, family that are led by a matriarchs, who is the oldest female in the group. It is also established that the matriarch, through complex acoustic and probably, olfactory signalling, exert tremendous influence over the group on where to go, when to leave a habitat patch, and when to attack during group defence and what species of animal to attack and in what set of circumstances. It is also reported that matriarchs play a leadership role in movements of female groups to distant habitats along certain used routes. If the behaviour by the oldest female is to make any sense, it needs to be viewed in evolutionary terms. Family groups are constituted of closely related individuals and by living and moving as a group, females are likely to increase their fitness value compared to if they were to live and move singly or with their young calves. However, group living creates a challenging environment to elephants because of their enormous forage (average, 170kg fresh plant mass/day/adult animal) and water (on average, 150Its/day/adult animal) requirements and increased competition for these resource as group size increase. Despite these challenges, large aggregations, some containing as many as 500 individuals are common in savannah subs-species of the African elephant (Loxodonta africana africana) during the wet season. It is clear that family units prefer to assemble and form large aggregation when conditions are favourable following onset of rains, and c;!)sband into individual units or sections of family units when conditions are severe such-as during dry season or droughts