|| 要旨トップ | 目次 |||日本生態学会第63回全国大会 (2016年3月、仙台) 講演要旨
一般講演（口頭発表） E2-33 (Oral presentation)
While group decision making has been well studied in many species, ontogenetic differences in collective behaviour of animals moving in dangerous situation are less known. In such a situation, more experienced individuals may take the lead positions and their decisions may affect other group members. Elephants have a matrilineal society, live long period and mature slowly. Wild Asian elephants ranging in Mudumalai National Park, southern India, often cross busy roads and are disturbed by vehicles very often. In this study, we compared behaviour between adult females and immature individuals from 44 events of road-crossing in groups. Average group size was 6.9. Before the crossing, a group waited 19 minutes at the roadside, on average. The ratio of adults entering the road first was higher than immature individuals doing so. Adults tended to stay longer on the road than the immature individuals. It may be considered that adults assessed the timing of crossing the road and crossed the road first to lead the group. Immature individuals that are less experienced and smaller than vehicles seemed to get more nervous and crossed faster than adults.