Although many animals use simple tools, only human beings, whose use of stone tools dates back hundreds of millennia, have been observed using tools to make other tools.
While one may apply the term tool loosely to many things that are means to an end , strictly speaking an object is a tool only if, besides being constructed to be held, it is also made of a material that allows its user to apply to it various degrees of force. If repeated use wears part of the tool down , it may be possible to restore it; if it wears the tool out or breaks it, the tool must be replaced.
