Humans aren’t the only species that calls on older relatives for babysitting help. Killer whales also rely on grandma to help watch the little ones, and a team of UK researchers aims to find out why.
Their current theory? Menopause, which is only found in orcas, pilot whales, and humans. The scientists, from the universities of Exeter and York, secured nearly £500,00 from the Natural Environment Research Council (NERC) to analyze data from more than 550 killer whales collected over 30 years by the Center for Whale Research.
The team will study how a post-menopausal whale helps its grandchildren survive. "If an older female gives birth at the same time as one of her daughters then the two calves will be in competition,” Dan Franks of the University of York told the Underwater Times. “Theory predicts that the calves of the older mother should lose out in this competition. So it makes sense for the older female to give up her reproductive rights and instead help raise the younger generation's offspring."
For more on orca family dynamics, read Outside's "Killer in the Pool."