Birds are not merely descendants of dinosaurs — they are dinosaurs. For Yale evolutionary biologist and ornithologist Richard Prum, birds have been a lifelong passion and a window into some of evolution’s most intriguing mysteries.

In a wide-ranging conversation with co-host Janna Levin, Prum traces the deep evolutionary origins of feathers, which he argues first emerged not for flight but for insulation, camouflage and display. Their colors — often invisible to the human eye — come into sharp focus under birds’ ultraviolet vision, suggesting a sensory world far richer than our own.

Prum also explains why he champions Darwin’s once-marginalized theory of sexual selection, which proposes that traits such as the peacock’s tail evolved not for survival, but simply because they were attractive. Beauty, in other words, may shape life as powerfully as utility.