1941: Bird Skulls and Vocalizations Apr 8, 2020

Birds have very different ways of producing vocal noises, such as with the syrinx, but that is far from where the differences stop. The aptly named 'hornbill' uses not merely the shape of its bill but the whole structure of its skull (as visible below on the left) to produce its vocalizations, making them louder and deeper. It is less certain, but some have speculated that this is what the large crown atop the head of a cassowary (as seen below on the right) is for as well, though the evidence is less conclusive, and its purposes may be promaily visual.

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