Why did birds lose their teeth? Was it so they would be lighter in the air? Or are pointy beaks better for worm-eating than the jagged jaws of dinosaur ancestors?
Actually, birds gave up teeth to speed up egg hatching, a research paper published Biology Letters on Wednesday suggests, challenging long-held scientific views on the evolution of the toothless beak.
Compared to an incubation period of several months for dinosaur eggs, modern birds hatch after just a few days or weeks. This is because there is no need to wait for the embryo to develop teeth — a process that can consume 60% of egg incubation time, said researchers Tzu-Ruei Yang and Martin Sander from the University of Bonn.
While in the egg, the embryo is vulnerable to predators and natural disasters, and faster hatching boosts survival odds. This would be a concern for dinosaurs and birds — all egg layers. In mammals, embryos are protected inside the mother. “We suggest that (evolutionary) selection for tooth loss (in birds) was a side effect of selection for fast embryo growth and thus shorter incubation,” they wrote.
Had teeth, lost them later
Previous studies had concluded that birds — living descendants of avian dinosaurs — lost their teeth to improve flight. Other studies had concluded that beaks were better for eating bird food.
