Feathers, wishbones and more were a dino thing before they were a bird thing
The asteroid strike (or was it the roiling volcanoes?) that triggered dino doomsday 66 million years ago also brought an avian apocalypse. Birds had evolved by then, but only some had what it took to survive.
Biologists now generally accept birds as a kind of dinosaur, just as people are a kind of mammal. Much of what we think of as birdlike traits — bipedal stance, feathers, wishbones and so on — are actually dinosaur traits that popped up here and there in the vast doomed branches of the dino family tree. In the diagram below, based on one from paleontologist Stephen Brusatte of the University of Edinburgh and colleagues, anatomical icons give a rough idea of when some of these innovations emerged.
Story continues after graphics.