We love eggs scrambled, fried, or poached; we couldn’t enjoy a quiche, meringue, or flan without them. But for scientists and archaeologists, these perfect packages are a source of both wonder and curiosity. Why do eggs come in such a spectacular variety of colors, shapes, and sizes? Why are we stuck mostly eating chicken eggs when our ancestors feasted on emu, ostrich, and guillemot eggs? In this episode, we explore the science and history of eggs, from dinosaurs to double-yolkers!
The ornithologist Tim Birkhead is the author of a book about eggs, titled The Most Perfect Thing, and as a result, people frequently ask him which came first, the chicken or the egg. “Everybody thinks they’re asking it for the first time,” he said. “And, of course, it’s eggs that came first.” Dinosaurs laid eggs long before their descendants, the birds, took flight. In fact, as the evolutionary biologist Mary Caswell Stoddard told us, the hard-shelled egg is the technological revolution that allowed birds to evolve. Leathery dinosaur eggs had to be laid somewhere moist, because they needed external liquid to provide water to the growing baby dino (as most reptile eggs still do today), while the bird egg’s solid exterior created a protective wall around the water already inside the egg. And so birds could move away from water to reproduce, because these new hard-shelled eggs could be laid just about anywhere.