Why is our Skeleton on the Inside?

For every species with bones, there’s at least 20 species on Earth with exoskeletons instead.

Having bones is pretty cool. They make our blood, let us hear, and keep us from being just a squishy puddle on the floor.

The exoskeleton animals are incredibly tough and strong.

So why don’t WE have our skeletons on the outside? This is the story of bones!

[Youtube]