National Geographic : 2010 Sep
PHOTO: JOEL SARTORE WILD Tail Spin To escape a predator, it doesn't cost some lizards an arm and a leg---just a tail. The wiggling appendage is left behind as a distraction as the lizard gets away. Special cells at the fracture site then trigger growth of a new tail. Several amphibians and reptiles possess an ability to regrow portions of a lost tail or limb. Now some of the cells that make this happen are getting attention from researchers. A 2010 Harvard review of amphibian regeneration-cell research included how findings could relate to human stem cells, which can also produce new tissue. "The promise will be to figure out what's the same and what's different about regeneration mechanisms," says Cliff Tabin, a geneticist who worked on the review. He hopes scientists will learn how animals that regenerate "get limbs and muscle, then hook that up with the bone, and have nerves seamlessly connect to the rest of the nervous system." Even if animal and human cells aren't found to regenerate in similar ways, the comparison "can give us a direct model to be applied to clinical studies," says Tabin. "It's a creative way to improve human health. " ---Dana Cetrone The regeneration process went slightly awry for this day gecko, which lost its tail---and grew back two.