Post-menopausal killer whale mums protect their large adult sons from injury by intervening and mediating when their offspring get into fights. Female orcas live up to 90 years in the wild. Previous studies show that even after having their last calf, killer whale mothers take care of their families by sharing the fish they catch, meaning they have an important role after they are no longer capable of reproduction. Now, in a study published on 20 July 2023 in the journal Current Biology, researchers note that these mothers also protect their boisterous male children into adulthood. However, they do not feel the need to do the same for their daughters. The research team studied southern resident orcas, a group of orcas that live off the Pacific Northwest coast. These killer whales live in matriarchal social units that consist of a mother, her offspring, and the offspring of her daughters. Although male orcas will outbreed with whales from other pods, both males and females stay in their unit of birth, with their mother, for life. Killer whales have no natural predators other than humans, so a tooth mark that is able to puncture an orca’s skin was most likely inflicted by another orca. The study found that, if a given male’s mother was still alive and no longer reproducing, that male would have fewer tooth marks than his peers.
