Sled Dog Science; June 2009; Scientific American Magazine; by Krista West; 2 Page(s)

With tongue and tail wagging wildly, Larry the lead dog crossed the finish line in March in sunny Nome, Alaska—after running 1,131 miles to win the Iditarod Trail Sled Dog Race for the third year in a row. To most mortals, Larry looks like a happy but nondescript, scrawny mutt. To sled dog mushers, he is a mini legend that simply needs no introduction. To scientists, Larry may hold the key to a physiological mystery.

Specifically, sled dogs seem to flip an internal switch that acutely changes how they burn fat calories, allowing them to keep going and going and going with no obvious pain. Figuring out how that mechanism works may have implications for human diabetics and those battling obesity.