Cave men, the very mention brings up images of, well...caves, and...men. But isn't this possibly a misnomer; quite possibly isn't it more likely that the name is bastardization of the more contemporary term 'man cave?' If you have 2 minutes to set aside to watch this video, I would have to say that you have too much time on your hands...and most likely won't find the answer here anyway.
Part of AnimeStudioTutor.com July 2017 animation competition - it's free to sign in and vote - and they won't contact you with any junk - or anything for that matter.

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Added on the 7 Oct, 2017

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