I wonder though about the evolutionary advantage of a freely rotatable head. If most aquatic creatures can already see roughly 180 to 360 degrees around them, it seems like a rotatable head only buys a little extra adaptability - at the cost of the energy needed to move the head.
(I mean, it's great to be able to turn your head and spot a predator, but then you have to manage it while fighting with the predator, or turn it back in the direction toward which you flee.)
Very cool post!
I wonder though about the evolutionary advantage of a freely rotatable head. If most aquatic creatures can already see roughly 180 to 360 degrees around them, it seems like a rotatable head only buys a little extra adaptability - at the cost of the energy needed to move the head.
(I mean, it's great to be able to turn your head and spot a predator, but then you have to manage it while fighting with the predator, or turn it back in the direction toward which you flee.)