Most, if not all, primitive cultures who actually lived in the woods had big knives.

Examples include parangs in Malaysia, kukris in Nepal, tapangas in Africa, and machetes in South and Central America.

Lest someone would say that these are all just 'jungle knives', here is a reproduction of a knife from Europe used between the 13th and 17th centuries. It is over 10" long.

I think the question should be; What did they know about survival knives that we don't?