April 20, 2024

Post-menopausal orcas are also pregnant with helicopters

The matriarchal structure of orca society is well known, and females can live up to 90 years and play a vital role in providing information to the younger animals. Previous research It suggests why these women live so long after they stop reproducing – 22 years on average – which suggests they play an older role in society, passing on culture, language and more to the younger members.

Now, new insights suggest that southern resident killer whales are post-menopausal (Orca orca) play a key role in keeping young male cubs out of a brawl.

“We were delighted to find this specific advantage for males with their post-reproductive mother,” said lead author Charli Grimes, from the Center for Animal Behavior Research at the University of Exeter.

The researchers analyzed almost 7,000 images of the orcas, which live off the US Pacific coast, and found that the males watched by a post-menopausal mother or grandmother had far fewer tooth rake marks than the ‘battle cricks’ made by other orcas during fights.

“Tooth rake marks are indicators of physical social interactions in killer whales and are usually acquired through fighting or rough play,” Grimes said. “These men had 35% less tooth marks than other men.”

Motherless males had 45% more tooth rake marks.

Although scientists are not sure how the females intervene in the conflicts of the young – it could be through their complex speech – physical intervention is unlikely because the senior organisms did not have higher rates of scaring than their younger counterparts.

Also, mothers who were still breeding did not show this style of protective helicopter parenting, suggesting that it is a specific behavior associated with the post-menopausal orca life stage.

“We can’t say for sure why this changes after menopause, but one possibility is that the cessation of breeding frees up mothers’ time and energy to protect their sons,” Grimes said.

As your daughters? It’s not a concern. The researchers note that because males will ‘push out’ with some females of other parts, there is an evolutionary need to ensure that genes are passed on. And because of more competition between young men, an elder bodyguard is useful. Injuries from tooth rakes can lead to infection or worse.

“The older females may use their experience to help their sons connect with other whales,” said Darren Croft, a professor at the University of Exeter. “They will have previous experience with individuals in other pods and knowledge of their behavior, and may be able to guide their sons away from potentially dangerous interactions.

“The mothers could also intervene when there seems to be a fight,” he said.

The study was published in the journal Current Biology.

Source: University of Exeter

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