"Our results show that closed-mouth vocalisation has evolved at least 16 times in archosaurs, a group that includes birds, dinosaurs and crocodiles. Since birds descended from dinosaurs, the research may also shed light on how dinosaurs made sounds. Closed-mouth vocalisations are sounds that are emitted through the skin in the neck area while the beak is kept closed. In total, the researchers identified 52 out of 208 investigated bird species that use closed-mouth vocalisation. Birds making closed-mouth vocalisations usually do so only to attract mates or defend their territory.

Source: dna July 12, 2016 14:15 UTC