How would you like to live five times longer than a mammal your size has any right to expect? Sounds great, right? But, wait. Would you still be interested if it meant you had to live out your days looking like a tiny alien dressed in an old sock made from the skin of somebody's hard-living grandpa?
Sure, take a minute to think it over.
Naked mole rats (Heterocephalus glaber) have made their evolutionary choice in this regard — this cold-blooded rodent is incredibly long-lived: They routinely live to the ripe age of 35, compared to porcupines and guinea pigs, close relatives which usually live no longer than age 8. They very rarely get cancer, are nearly incapable of feeling pain and when the oxygen runs out in their underground tunnels, they basically start acting like plants.
In a study published Jan. 24, 2018, based on analysis of the life histories of thousands of naked mole rats, researchers found that while the rodents not only live incredibly long lives, they also don't really age. Seriously, their risk of dying just doesn't really seem to increase as they get older, and female fertility doesn't even seem to decline with age.
Defying the Odds
Study author Rochelle Buffenstein, a comparative biologist who works for the longevity-focused California biotech company Calico, has studied naked mole rats for more than three decades, and has recorded the life history of each of the 3,329 animals that have passed through her lab in that time. What she has found is that naked mole rats are a huge exception to the freaky Gompertz law of mortality, which was developed in 1825 by British mathematician Benjamin Gompertz to assign a mathematical formula to the phenomenon of aging. For humans, Gompertz law states that after the age of 30, the likelihood we're going to die doubles every eight years. Some variation of this law applies to basically every other mammal we know about, with the exception of Buffenstein's lab-reared mole rats.
Because once Buffenstein's naked mole rats reached sexual maturity at about 6 months of age, she found the likelihood that they would croak reached around 1 in 10,000, where it hovered for the rest of their lives. Since only a few of Buffenstein's naked mole rats were not killed in experiments or moved to other labs, we don't actually know how and if the naked mole rat's strong longevity game eventually hits a wall — the oldest individual in the study is currently 35 years old. So who knows! Aging could happen really quickly for these little superheroes after a certain point in time.
So, for the rest of the over-30 mammal crowd out there — try to have a great day today in spite of the fact that the likelihood of your death is roughly doubling by the decade!