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Male elephant seals behaviour: fights and matings

The core of this research project is collection of behavioural data: in particular we are interested in variation of tactics of competition and breeding of different males. The most impressive component of male elephant seals behaviour is fighting: to get control of an harem, and be able to reproduce, a male has to defeat all the competing males of the same breeding area. Then, to maintain the control he has achieved, he has to constantly keep other males away from females of the harem by enforcing his status by vocal and visual displays. The result of this intense competition is a huge skew in mating: a few males get control of an harems, and may fertilize up to one hundred females (the estimated fertilization success of the most successful male of Sea Lion Island was 108 females in 1995, 110 in 1996 and 123 in 1997), while the most of the other males don't copulate at all. Hence the variation in competitive abilities results in a large variation of breeding success, and this drives an intense sexual selection. By doing thousands of hours of observation of agonistic and breeding behaviour, and by videotaping fights, we hope to be able to determine which components of male phenotype build up a successful fighter and mate.

Studying elephant seals

The excellent condition for field work offered by Sea Lion Island (and elephant seals !)