S-bend

Evolution doesn’t result in perfection, but in ridiculous compromises, recoveries from enforced limits and the sheer variety of difference achieved using the same basic pattern. Take necks. Humans have seven bones in their necks. These vertebrae are standard for almost all mammals, whether you’re a mouse or a giraffe, seven vertebrae is the standard. Birds are different. Birds have between thirteen and twenty-five vertebrae and have super-flexible necks. That means they can feed and preen and live very different lives using long necks.

Exhibit A:

This young Mute Swan has an s-bend in its neck to marvel at. As long as I don’t imagine myself having a neck like that, I’ll be fine. If I do, I’ll just have to give my head a wobble, just not a very flexible wobble.