Orca mums give their sons a whale of a time

Scientists have found that male killer whales who still lived with their mothers were less likely to get into fights.

An orca at Ningaloo Reef in WA. Picture: iStock

The phrase “orca mum” may soon come into use in parenting after scientists found that male killer whales who still lived with their mothers were less likely to get into fights – suffering far fewer injuries thanks to protection from a strong, matriarchal figure.

Orcas and humans are among only five species of mammal to experience the menopause. Once a female orca passes reproductive age, she sticks around to lead her family unit and share fish with her children and their offspring.

Scientists have now found that post-menopausal orcas also provide protection for their sons but not for their daughters.

A female orca can live for up to 90 years in the wild, living for an average of 22 years after menopause. Male and female orcas tend to stay in the same matriarchal unit with their mother for life, with most units consisting of a mother, her sons and daughters, and her daughters’ offspring.

A study published in the journal Current Biology has found that if a male orca’s mother is still alive and past menopausal age, that male orca will have fewer tooth marks from attacks and fights than a male whose mother is dead or of reproductive age.

Researchers from the University of Exeter did not find a large number of tooth marks on the female orcas, suggesting they were not “physically intervening” in fights to defend their sons, but “might be acting as mediators to prevent conflict from occurring in the first place”.

“It’s possible that with age comes advanced social knowledge. Over time, they might have a better understanding of other social groups,” Charli Grimes, an animal behaviour scientist at the University of Exeter, said. “Given these close mother-son associations, it could also be that she is present in a situation of conflict so she can signal to her sons to avoid the risky behaviour they might be participating in.”

The Times