Male dolphins forming alliances father more babies

Male dolphins who co-operate with each other have more sexual success, a new study by a team at Macquarie University has revealed.

The study found that male dolphins who form an alliance fathered far more babies than those who worked in smaller groups or alone, ABC Science reported.

For the finding, the researchers studied a population of 70 male and 64 female Indo-Pacific bottlenose dolphins living in Port Stephens, New South Wales.

They collected skin samples from males and calves and looked for genetic markers, which would reveal the paternity of the calves.

They found that 14 different males had sired 32 calves. However, nearly half of the calves – 13 individuals – were sired by a single alliance of four dolphins known as The Beatles.

Three calves were sired by a three-male alliance and five calves were sired by another three-male alliance. The remaining 11 calves sired by pairs or lone males.

“This research shows that male dolphins need to cooperate with each other to maximise their reproductive success,” said co-author Dr Jo Wiszniewski.

“Males in alliances have better control of the females – we often see the males swimming around the females one on each side, sometimes one at the back. The female can’t get away from them.

“They basically herd the female – they try to keep her away from other males. They would swim by her and when she was feeding, they would feed too.”

“These kind of herding events can last just from a few hours up to a few weeks at a time,” explained Wiszniewski.

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The findings have been published in the Journal of Animal Ecology.

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