3 of 24: In this Oct. 21, 2009 photo, an older naked mole rat is shown at the Barshop Institute at the UT Health Science Center in San Antonio. Naked mole rats are becoming more popular in research laboratories, where the seemingly invulnerable rodents have surprised scientists with their ability to live up to 30 years and their potential to offer insights into human health. They're being used to study everything from aging to cancer to strokes. (Photo/AP Photo)

Share this gallery