[usrnm]

> the Denisovans developed stone tools tens of thousands of years before our own species

I wonder if it's possible that stone tools were developed only once by some early species and then just passed down through generations? What do we really know about those times?

[gus_massa]

Stone tools are very arkeological friendly, because they don't rot and because they are not reused later (like iron tools or marble blocks). So the story of stone tools is well documented. https://en.wikipedia.org/wiki/Stone_tool

A few of our ancestor species used the exact same model of stone hand tool (it's like a small axe) for a million years! It was even inherited between a few species.

Something like 1.5 million years ago, someone had the brilliant idea of improving it. It was another of our ancestor species. (I think that Denisovans branched before this but IANAA.) After that there are a few (slow) step of progressing.

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You may be interested to read about https://en.wikipedia.org/wiki/Clovis_culture Some theory says that they were the first human to reach America. Other theories says that humans had already come to America but they had older stone technology and the Clovis people just brought the new stone technology that was much better. I can't find a clear report, and I'm not sure if there is a clear evidence of both theories. It's easier to track the use of the new arrow heads than track the users.