Turtles & Tortoises & Negative Senescence

A giant Galápagos tortoise, only as old as it feels. Meridith Kohut for The New York Times

When I learn a new word–even if it is a word I cannot picture using in conversation but it represents a concept that is interesting and surprising, I consider that a good day. Jack Tamisiea, thanks for the science reporting here, and especially for the word senescence:

Tortoises and turtles don’t just live for a long time — they barely age while they live.

The black marsh turtles displayed negative rates of senescence, meaning their mortality risk decreased as they aged. iStock/Getty Images

For mammals like humans, aging is inevitable. No matter how many vitamins we take, skin sags, bones soften and joints stiffen over time. However, turtles and tortoises age more gracefully. Despite their wrinkled skin and toothless gums, species like Galápagos giant tortoises seem unscathed by the ravages of aging. Some show few signs of slowing down as they plod into their 100s.

To determine what drives these ageless wonders, two groups of researchers examined turtles, tortoises and their ectothermic, or coldblooded, brethren in a pair of studies published Thursday in the journal Science. Continue reading