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Old Age Doesn’t Seem to Kill Naked Mole Rats

The wrinkly rodents are as likely to die at the age of 1 as they are at 25, according to a new study

(Meghan Murphy, Smithsonian’s National Zoo)
smithsonian.com

How are naked mole rats weird? Let us count the ways: They’re cold-blooded mammals, they organize their breeding colonies like insects, they turn into super babysitters after eating poop, and they can survive for up to 18 minutes without any oxygen. As Kai Kupferschmidt reports for Science, a new study has found that these bizarre critters also appear to defy everything we know about the way mammals age—and could hold clues to slow aging in humans.

Rochelle Buffenstein, a comparative biologist at Calico Life Sciences, has been studying naked mole rats for the past 30 years. She recorded the date of birth and death of every rodent in her lab, also noting if the rats were killed for experiments or sent off to other researchers. In total, she amassed data on 3,329 naked mole rats, according to Stephanie Pappas of Live Science. The results of her study, published in the journal eLife, revealed something incredible: after they reach sexual maturity at six months, naked mole rats have a one in 10,000 chance of dying—no matter how old they are.

This trend flies in the face of an oft-cited mathematical model describing how mammals live and die. According to the Gompertz law, a person’s risk of death increases exponentially with age; after the age of 30, that risk doubles every eight years. The law was thought to apply to all mammals once they reach adulthood, but it does not seem to hold true for naked mole rats. The results of the new study suggest that if you are a naked mole rat, you are as likely to die at the age of one as you are at the age of 25. Or as Buffenstein put it during an interview with Pappas, “Your death is random.”

Though the study’s findings are surprising, researchers have long known that something strange is afoot when it comes to naked mole rats’ aging process. The wrinkly rodents have unusually long life spans; based on their size, they should only live for about six years in captivity, but they have been known to live past the age of 30. Breeding females do not experience menopause, and remain fertile even at an advanced age. Studies have also shown that naked mole rats have a unique cellular structure that appears to prevent them from getting cancer.

Because naked mole rats do not seem to age according to the Gompertz law, the authors of the new study have dubbed the rodents “a non-aging mammal.” Caleb Finch, a biogerontologist at the University of Southern California in Los Angeles who was not involved in the new study, tells Kupferschmidt of Science that this classification might be a bit premature; more research needs to be done to ensure that naked mole rats don’t begin aging at a much later point than most mammals.

Researchers also aren’t sure why naked role rats might not adhere to the Gompertzian model. But Buffenstein tells Pappas of Live Science that further investigations into naked mole rats’ aging process could have significant implications for humans.

“It is our absolute belief,” she says, “that when we find out what these mechanisms are they will give rise to interventions that could abrogate the aging process in humans.”

About Brigit Katz

Brigit Katz is a freelance writer based in Toronto. Her work has appeared in a number of publications, including NYmag.com, Flavorwire and Tina Brown Media's Women in the World.

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