Diurnal activity of the long-snouted dolphin Stenella longirostris longirostris, French Polynesia Activite diurne du dauphin a long bec de Moorea Stenella longirostris longirostris, Polynesie francaise
Thomere, F.
Bulletin de la Societe des Sciences Naturelles de l'Ouest de la France 26(1): 1-11
2004
ISSN/ISBN: 0373-3025
Accession: 038158277
In Moorea, a French Polynesia island, lives a quite stable pack of spinner dolphins (otherwise called long-snouted dolphins), Stenella longirostris longirostris, of about 150 individuals. This group comes to rest during day hours in the lagoon waters, and goes fishing during night in open water. These dolphins show a very changing aerial behaviour, as compared to other Delphinids. This behaviour was codified and measured in the day-time in order to determine if it was motivated by random or by a specific activity pattern. The results were then compared to those obtained by Norris et al. (1994) in Hawaii for the same species. It appears. for the both sites, that Cetacean society, based on fission-fusion relationships without obvious hierarchy, presents an increase in activity (aerial behavior) at the end of the afternoon, just before going hunting. With these daily-repeated activity phases, occurring at probably not fortuitous hours, dominance patterns and/or roles could be renewed every day. This opinion is emphasized by the fact that social behaviour are linked to an activity frame. Jumping significance should then be overlooked.