Crabs

Crabs1 are quite interesting animals. Crabs can:

• Grow enormous claws, some species only grows one claw, this is mainly used to flirt and fight; humans do the same thing, they will exercise to build up muscles to either just impress significant others or to be better, stronger fighters
• Dance to impress females (maybe some females dance too); humans do that every weekend (well... not all of us, but you see what I mean)
• Do something much more impressive: they can regrow a claw! So far, humans have not been able to regenerate themselves. However, we're getting there within our 20th century medecine.

• 1. There are many species of crabs, very small ones, large ones, some with small claws, large claws, and not too long ago, we found a species with hair!