Ancient ancestors of the squishy, modern cephalopods like octopus and squid all had shells to protect them from predators. 

In the beginning the shells were a literal life-saver for these creatures, but over time it became a huge weakness. 

Luckily these soft and vulnerable creatures were able to adapt to their environment and eventually lose their heavy, cumbersome shells. 

Can you imagine a modern octopus or squid with a hard shell over its fleshy body? 

Check out this exciting video from PBS Eons to learn more about these fascinating creatures and their ancestors. 

Leave a comment below to let me hear your thoughts about this interesting discovery!