【保全】人間の活動が盛んな地域で雄だけの群れを形成するアジアゾウ

Highly endangered adolescent Asian elephants have been observed forming all-male groups in land fragmented by human activity, according to a study published in Scientific Reports. Group formation in male elephants may be an adaptive behaviour to improve reproductive fitness in areas where the risk of contact with humans is high, the authors speculate.

Nishant Srinivasaiah and colleagues analysed 1,445 photographs of 248 individual male elephants that they collected across southern India over a 23-month period. The authors found that adolescent male elephants formed large bull groups when inhabiting non-forested or human-modified areas such as cropland. Conversely, sexually immature juveniles mostly lived in mixed-sex groups and sexually mature adult males were mostly solitary. The largest groups of adolescent elephants were found in areas with high crop availability, and individuals in these groups tended to have better body condition compared to solitary adult males. This finding indicates that group formation in young male elephants may be an adaptive behaviour to improve reproductive fitness in areas high in resources but with a high risk of human contact.

The authors show that large all-male groups foraging on cultivated land tend to cohabit for multiple years, suggesting that this behaviour could be a risk management strategy to survive in threatened habitats. They suggest that understanding the evolving behaviours of elephants living in areas with higher rates of human activity may help reduce human - elephant conflict and prevent further loss of these endangered animals.