Question: how do owls turn there head all the way round?

Ian Hands-Portman answered on 18 Mar 2014:

I’m not an owl specialist but I have handled owls and been out on a rescue misson to fetch a trapped one, they’re remarkable creatures.

I had to look this up ( but not on wikipedia 😉 ). Some of our neck arteries run though holes in the side of our back bones ( if you like oxtail you can see these on cooked bones ) the holes are quite tight and line up with each other. If we tried to turn our heads 270 degrees ( the maximum for an owl ) we’d crush the arteries as they’re pulled through the holes as we twist our necks.

In owls the holes are much larger – ten times bigger than the artery and they’re packed with cushioning layers of tissue so when the owl turns its head the artery has space to move and padding to stop it getting crushed against the bone.

Why does an owl need to do this though, and why don’t we ? – we move our eyes to look around but to see in very dim light an owl has to have huge eyes – so big they can’t move in the socket so the owl has to move its whole head instead.