Whales Don’t Get Cancer as Much as Humans — and Scientists Are Trying to Figure Out Why

Cancer is a leading cause of death for humans, with about 18 million cases worldwide in 2020. But other animal species aren’t as plagued by the disease. It’s particularly curious that large animals like whales and elephants have low rates of cancer, given that they have many more cells than humans and, therefore, should be at risk for more mutations that could lead to cancer. That concept is called Peto’s paradox, and scientists at the U.K.’s Wellcome Sanger Institute are working to figure it out. The research team studied various mammals that had died of natural causes at the Zoological Society of London, from lions, to giraffes, to mice, and lemurs, specifically looking at how many mutations they were accumulating each year. “What we found was very striking,” project leader Alex Cagan told The Guardian. “The number of mutations each was accumulating every year varied enormously. Essentially, long-lived species were found to be accumulating mutations at a slower rate while short-lived species did so at a faster rate.” There are still many unanswered questions before Peto’s paradox can be considered solved — namely how and why longer-lived species have a slower mutation rate — so the scientists will next be turning their attention to cells in other living things, including plants, insects, and reptiles.

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