The evolution of human athletic prowess over the millennia is where Bernd Heinrich begins his essay, "Endurance Predator," which kicks off this month's cover package and photo gallery, "Ascent of the Athlete" (page 66). The University of Vermont professor has devoted considerable thought to these questions in his 40-year career as a comparative biologist and as the author of books like the award-winning Mind of the Raven—not to mention as a record-breaking ultradistance runner. An expert on African dung beetles, bumblebees, and ravens, Heinrich has lifted ideas for improving his own endurance straight from the techniques of other species. At age 41 he entered his second ultramarathon, a 100-kilometer (62-mile) race, with a little inspiration from tree frogs (the amphibians are able to chirp all night—the equivalent of running ten hours at medium pace—by varying the length of their chirps). He also took a cue from camels, which top out at ten miles per hour yet regularly cover 100 miles in 16 hours, to maintain a slow, steady race pace. Heinrich won the event in six hours, 38 minutes, and 21 seconds, setting a U.S. record and a masters world record that remains unbroken.

As animal physiology helped Heinrich set his mark, it can also foretell human potential. Will Olympians ever demolish our current records—say, run 100 meters in under nine seconds or a mile in under three minutes? (Heinrich will explore these possibilities at greater length in his 12th book, Racing the Antelope: What Animals Can Teach Us About Running and Life, due out next spring from HarperCollins.) Either way, there's no doubt that the roots of Olympic competition are in the endurance tests our ancestors faced as hunters. "The allure is in the chase," says Heinrich, now 60, who trains on the trails near his Burlington, Vermont, home. "Still, I don't have to chase after antelope for my lunch. I can eat as much as I want, and I could become a lardass, I suppose. But I like to run, and I do almost every day."