Las female killer whales they can live up to 90 years but the last 20 are no longer fertile. But why do they spend such a long period of their lives without reproducing? According to a study, they do it to take care of their sons and protect them from attacks by other orcas.
Previous work had shown that, even after giving birth to their last calf, mothers care for their families by sharing the fish they catch, but now a new study has found that these mothers also support their children socially by protecting them from fights.
The details of the research have been published this Thursday in the journal ‘Current Biology’. “The aim of the project was to understand how these post-reproductive females help their young and our results show that menopause is adaptive in killer whales,” explained first author Charli Grimes, an animal behavior scientist at the University of Exeter.
For the study, the researchers studied a group of killer whales that live off the Pacific Northwest coast. These killer whales live in matriarchal social units made up of a mother, her cubs and the cubs of her daughters.
Using data from the Center for Whale Research’s annual photographic census of the orca population, the researchers looked for scars on the skin of each orca recorded.