WHAT IS THE EVOLUTIONARY ADVANTAGE...

of rhythm?


Cockatoo bobbing its head to the beat.
Why is it so?

Not an expert on the Cockatoo, but it's bobbing probably stems from its ability to parse sounds in succession, which was put there via sexual selection.

Sexual selection is just as real as the natural variety. Which is why mandarin baboons have the "war paint" blue and red face. And why certain baboon females have what almost amounts to a large swollen growth where they sit. Which is why song birds have such a large number of complicated and learned songs. The females just like those kind of intricate filagree things. Yet another example is the Elk with its many pointed horns. The horns can be deadly, but they're also very ornamental, made of bone and can snap... leading to nervous inefficient male-vs-male battles.