AsianScientist (Oct. 27, 2011) – Marine biologist Joanna Wiszniewski of Australia’s Macquarie University has observed a fascinating approach to mating among the Port Stephens Indo-Pacific bottlenose dolphins.
According to a recent research paper published by the Journal of Animal Ecology, groups of male dolphins who put aside their sexual competitiveness and form alliances with each other to seek out and reproduce with females have better reproductive success than males who go it alone.
“These results are fascinating because it demonstrates that male bottlenose dolphins need to cooperate with each other to maximize their reproductive success,” said Wiszniewski.
The alliances are usually made up of two to four males and can vary in stability with some alliances lasting just a season while others can exist over many years. Alliance formation is a highly complex and long-term process that involves a high level of mutual tolerance, cooperation, and coordination.
While alliances among dolphins and some other mammals have been observed before, previously there has not been a lot of evidence to show why an alliance might be preferable. What this research has found is that the more alliance partners a male has, the more successful he is at reproducing.
“We found that most of the males who were fathering offspring in this population were members of large alliances. These results explain that the benefit for some male species to form alliances is to gain mating opportunities,” she said.
The finding that male dolphins share mating opportunities with their alliance partners and will risk increasing their partners’ reproductive success at a potential cost to themselves, indicates that dolphin relationships are based on a high level of mutual tolerance and cooperation.
“The level of cooperation and tolerance observed among dolphins is unseen in most animals. This research is important to understanding how these complex relationships operate,” she said.
The article can be found at: Wiszniewski J et al. (2011) Male reproductive success increases with alliance size in Indo-Pacific bottlenose dolphins (Tursiops aduncus).