Female social organisation in an Asian elephant population in southern India
Nandini R. Shetty, Keerthipriya P., T.N.C. Vidya. Evolutionary And Organismal Biology Unit, Jawaharlal Nehru Centre For Advanced Scientific Research, Jakkur, Bangalore 560 064. Email: Nandinis@Jncasr.Ac.In
While African savannah female elephants are known to show a fluid, multi-tiered, fission-fusion society, female Asian elephant social organisation is not well understood. The structure of female Asian elephant society can have implications on elephant management and conservation. We, therefore, carried out the first quantitative study of female Asian elephant social organization in India by observing over 250 identified adult females.
We collected association data on 273 individually identified adult females in Nagarhole and Bandipur National Park from 2009 March to 2012 June. Network analysis and cluster analysis were used to check whether adult females showed preferred associations and to identify various levels of social organization. Fourteen microsatellite loci were used to estimate the genetic relatedness between adult and sub-adult females.
Adults females showed preferred associations, and adult and subadult females within family groups were first or second order relatives. There was fluid, multilevel social organisation, with between-group variability in association patterns. The social network was more cohesive than previously studied elephant networks at low association indices, but less cohesive at high association indices, suggesting individual females and clans as important social units.
Social organization influences the spread of information and survival strategies. Since clans represent stable social levels rather than family groups, these large social entities rather than family units will have to be taken into account in planning management interventions in the landscape. This also suggests that the study of between-clan interactions may be important in understanding the effect of the dam constructed in the study area on foraging and ranging.