Doting killer whale grandmothers help their grand calves survive, particularly in times of food scarcity, scientists reported in a paper that sheds new light on the evolutionary role of menopause. Orca females stop reproducing in their thirties or forties but can continue to live for decades more, a phenomenon known only to exist in humans and four other mammal species, all of which are whales. It has been suggested that the trait evolved because it allowed post reproductive females to help their wider kin – referred to as the “grandmother effect” in people, but the theory had not been tested in whales until now. Canada: endangered orca pod produces its first calf in three years Read more “This is the first non-human example of the grandmother effect in a menopausal species,” senior author Daniel Franks from the University of York said. “It has also been shown in elephants, but they are able to reproduce until the end of their lives. We currently know of only five species that go through menopause: the others are short-finned pilot whales, narwhals and beluga.” Writing in the Proceedings of the National Academy of Sciences, Franks and colleagues examined more than 40 years of […]
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