Beavers teeth never stop growing, they must constantly gnaw on objects to keep them at a manageable. Their teeth would eventually grow into their brain if they didnt maintain them.

                                  Snails can grow back a new eye if it loses one.

                                    You can tell a tures gender by the noise it makes. Males grunt and females hiss.

                                    Giraffes have no vocal cords and their tongues are blue-black in color.