by James Morris
Illustrations by Talia Niederman

What’s a vertebrate? That’s easy – A vertebrate is an animal with a backbone.

Not so fast. It turns out that not all vertebrates have a backbone. That is, they don’t have the bones that make up the backbone, called vertebrae. Hagfish, for example, don’t have vertebrae, but are classified as vertebrates.

That doesn’t make sense. How can a vertebrate not have vertebrae? Continue reading →