The tremendously long tails of male Ribbon-tailed Astrapias don’t help them survive, in fact they get in the way. Males sometimes have to pause to untangle their tails before they can fly away—not a survival advantage. But the tails do help them attract females. And by carefully choosing their mates, the females determine which males’ genes—and what kinds of tails—survive to the next generation. Filmed and photographed by Tim Laman. Explore more at