Birds' voiceboxes are in their chests instead of their throats like mammals and reptiles. Scientists aren't sure how or why birds evolved these unique voiceboxes, but a new study sheds some light on how they came about. Similarities in the windpipes of birds, crocodiles, cats, mice, and salamanders suggest that birds' weird voiceboxes might have arisen from a windpipe reinforcement. From this, scientists can learn about the sounds bird ancestors — dinosaurs — made.