Name a tool everyone uses..

I've seen this before on the nature shows, pretty interesting stuff.
As an aside Goodall was a hell of a courageous OR crazy person, those seemingly snuggly cuties could tear a human body into red confetti.

I've seen docs where lions and gorillas engage in clan like behavior, pushing into territory and violently fighting over feeding grounds.

Probably the best tool in my box. It's your second set of hands.

Brings up an interesting distinction: Tool vs Instrument.

I'd say a ruler is an instrument, a tape measure is a tool.