By Sarah Baker
Image Credit: National Geographic
The naked mole rat – a rodent the size of a mouse that lacks hair and has wrinkly skin – is perhaps best known for its strange appearance. This creature has been of interest to scientists previously for many unique characteristics it possesses: its seeming resistance to developing cancer, eusocial behavior living in colonies of up to 300 individuals, ability to survive without oxygen for almost 20 minutes, and the fact that females can bear children for the entirety of their lives without ever reaching menopause. And now, it has been found that they possess another exceptional feature – researchers at Calico showed in eLIFE that naked mole rats seem to defy normal laws of aging.
Not only are naked mole rats the longest lived rodent, with a life span of greater than 30 years, but they also do not show the same physiological decline associated with aging in other animals, including decreased heart function, decreased bone quality, and metabolic decline. Furthermore, they rarely develop chronic diseases normally associated with age. The authors of this study compiled data on over 3,000 naked mole rats and tested whether they fit into the “Gompertz-Makeham law of mortality” which suggests that mortality risk increases with age. For example, in humans, after we reach the age of 30, our risk of death doubles every 8 years. This makes sense for the aging of most animals as decreased health tends to occur later in life, but since naked mole rats do not show normal physiological decline, they wanted to see if they defied this law as well.
When all data was analyzed, these researchers found that naked mole rats indeed violated the Gompertz-Makeham law of mortality. This has never been seen in any other mammal – even very long-lived species show physiological decline at some point in their life. This lack of “aging” in the naked mole rat was independent of either sex or breeding status, and thus was observed throughout the species. The reason this is the case is still unknown, but is something that researchers hope to find the mechanism of, in hopes to uncovering the possible secret to delay aging in humans.
Original Article: https://elifesciences.org/articles/31157
Further reading: http://awesci.com/gompertz-law-dreadful-law-death/