Early in pregnancy, something surprising happens. Every human embryo develops a tail. It is not symbolic or imagined. A real extension forms at the base of the spine, complete with vertebrae. Later, ...

Nature is full of surprises. A salamander can lose a leg and then, over weeks, grow it back as if nothing happened. Starfish can re-grow arms, while axolotls (a type of salamander) are known to ...

Mark Grabowski does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond ...