Riddles riddles and riddles

1. Other than the massive weight and strenth, what is strange about Elephants?

This isn't really a riddle, more of a unique fact ...

Elephants are the only animal with four knee joints, others have 2 knee joints and 2 elbow joints.

Not sure if that's a myth or not though.

~Pete.

I've studied that in school and it is true ^tpam