These creatures live more than five times longer than would be expected for their size. Research into the biological mechanisms underlying their longevity could suggest ideas for slowing aging in people.
?| December 21, 2011?|
Editor's note: This article is adapted from the book The Youth Pill: Scientists at the Brink of an Anti-Aging Revolution, by David Stipp. We are presenting it in conjunction with Stipp's article "A New Path to Longevity" in the January 2012 issue of Scientific American. Additional information can be found in "What Unusually Long-Lived Animals Say about Human Aging."
The study of aging tends to raise the kind of deceptively simple questions children ask, such as, ?Why did Spot, who was the same age as me, get old and die before I grew up?? Such queries quickly lead to deep mysteries, none of which are more riveting than those surrounding extraordinarily long-lived species.
One that has come to the fore in recent years is a grotesque, mouse-sized rodent called the naked mole-rat. Resembling saber-toothed sausages, they?re even weirder than they look. For one thing, they live in termite-like, underground colonies populated by workers that serve as a support system for a single breeding queen. But their most mind-bending trait is an incredibly slow rate of aging. In captivity they can reach about 30 years of age, ten times the typical life spans of their mouse cousins. To see how remarkable that is, imagine a species of primates with a life span of a thousand years.
The leading authority on mole-rat longevity is Rochelle Buffenstein, a researcher who maintains a sizable colony of the animals at the Barshop Institute for Longevity and Aging Studies, part of the University of Texas Health Science Center at San Antonio. When I visited her one afternoon, she led me to a dimly lit room where I found myself surrounded by scores of chirping mole-rats merrily tending their nests inside clusters of shoebox-sized containers connected by clear plastic tubes. To my surprise there was no airtight barrier protecting them from the outer world's germs. Mole-rats are so hardy, she explained, that there?s no need for that. Underscoring the point, she suddenly picked one up and handed it to me. It was ?the old man of the colony,? she said?her most senior mole-rat.
Up close he turned out to be oddly endearing, possessed of the bald, wrinkled, buck-toothed, querulous, squinty-eyed look of a slightly demented codger born well before the age of orthodontia. His exact age wasn't known?he?d been caught in the wild?but Buffenstein estimated he was pushing 29. It suddenly dawned on me that he might be the oldest rodent on the planet. I gingerly handed him back, feeling as if I?d been momentarily entrusted with a 2,000-year-old Han Dynasty vase.
The life style of the naked mole-rat Natives of East Africa, mole-rats were introduced to science in 1842 by Eduard R?ppell, a German naturalist known for heroically traipsing the biosphere and bringing pieces of it home. Despite their curious appearance, the rodents, officially named Heterocephalus glaber (meaning, roughly, weird-headed baldy), didn?t get much attention until Jennifer Jarvis, a Kenya-reared daughter of English missionaries, discovered in 1981 that they?re an extremely rare, mammalian version of social insects like termites. Each mole-rat colony is dominated by a large-bodied queen that mates with one to three consorts and produces hundreds of babies during her life. Intriguingly, the queens appear to keep workers in line by literally pushing them around, and when a royal mole-rat encounters a groundling in a tunnel she shoves it backward or walks over it. Such aggression appears to help suppress the lower orders? fertility, as well as cue their subservient behavior?rarely-shoved workers in tunnels remote from the queen's chamber reportedly tend to goof off.
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