Despite no longer reproducing, postmenopausal female whales play a crucial role in the survival of killer whales, researchers have found. With extensive knowledge of their environment, female whales in their 70s and 80s lead younger whales to food in times of scarcity.
Female whales are the only mammals other than humans to live for decades after menopause, often reaching ages of 90 or above. Male whales live about 60 years at most.
Researchers in Britain observed 750 hours of video footage of killer whales traveling. Older female whales, the scientists found, were significantly more likely than male ones to lead, and far more likely to do so in years when salmon were scarce.
“In years when there’s not much food around — and you assume finding food is much more important in those years — they are really out front,” said Lauren Brent, a behavioral ecologist at the University of Exeter and lead author of a study in Current Biology. “They know where the food is, so they’re taking leadership positions.”
As for why the male whales die younger, Dr. Brent pointed to differences in lifestyle.
“When they are younger, the males are competing with each other for mating opportunities,” she said. “If those interactions get aggressive, that could lead to higher mortality risks.”
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