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Talk about a mummy boy! Older Female Killer Whales Protect Their Sons From Fights (But Let Their Daughters Fend For Themselves!), Study Finds
- Experts studied the scars left behind when a whale scrapes its teeth on another whale
- Males had fewer markings when their mother was present and had stopped breeding
- This suggests that females protect sons – but not daughters – from attack
It is the highly intelligent marine mammals that are the ultimate apex predator of the ocean.
But according to a new study, some killer whales are actually mummy boys.
Researchers have found that older female killer whales protect their sons — but not their daughters — from attack.
They studied “tooth rake marks” — the scars left when a whale scrapes its teeth on another whale’s skin — and found that males had fewer marks when their mothers were present and had stopped reproducing.
The new study – conducted by the Universities of Exeter and York, and the Center for Whale Research – adds to growing evidence that postmenopausal women increase the life chances of their offspring, especially men.
Researchers have found that older female killer whales protect their sons — but not their daughters — from attack
The team studied southern killer whales, a group of killer whales that live off the coast of the Pacific Northwest.
These killer whales live in matriarchal social units consisting of a mother, her offspring, and the offspring of her daughters.
Although male killer whales reproduce with whales from other groups, both males and females remain in their natal unit, with their mother, for life.
The scientists found that males with postmenopausal mothers had 35 percent fewer teeth marks than other males whose mothers were still breeding.
Only six species — humans and five species of toothed whales — are known to experience menopause.
Lead author Charli Grimes said: ‘We were fascinated to find this particular benefit for men with their post-reproductive mothers.
“For males whose mothers were still breeding, we found no evidence that her presence reduced dental rake injuries.
“We can’t say for sure why this changes after menopause, but one possibility is that stopping breeding frees up time and energy for mothers to protect their sons.”
The team studied “tooth rake marks” — the scars left when a whale scrapes its teeth on another whale’s skin — and found that males had fewer markings when their mothers were present and had stopped breeding.
“Tooth rake marks are indicators of physical social interactions in killer whales and are usually acquired through fighting or rough play.”
The team added that males can mate with multiple females so they have more potential to pass on their mother’s genes – which could explain the protection.
Professor Darren Croft, who also worked on the study, commenting on how mothers protect their sons, said: ‘We can’t say for sure.
“It’s possible that the older females are using their experience to help their sons handle social encounters with other whales.”
“They have previous experience with individuals in other pods and knowledge of their behavior, and therefore can steer their sons away from potentially dangerous interactions.”
“The mothers can also intervene if a fight seems likely.”
He said the similarities to humans are “intriguing,” adding: “As with humans, it appears that older female whales play a vital role in their societies — using their knowledge and experience to provide benefits, including finding food and resolving conflict.”
The findings were published in the journal Current Biology.