The alternative explanation... (Score: 2, Insightful) by email@example.com on 2015-04-22 07:54 (#7JFJ) ...is that tool-using humans are older than they think, but that fossil specimens have not been recovered (and might never be). Re: The alternative explanation... (Score: 2, Insightful) by firstname.lastname@example.org on 2015-04-22 21:02 (#7M1Z) Or that the lines delineating human and proto-human species are blurrier than traditional taxonomy is adequate to describe. We don't have DNA samples from specimens that ancient, AFAIK. Re: The alternative explanation... (Score: 1) by email@example.com on 2015-04-23 19:22 (#7PBD) That too. I've often wondered how many of the specimens we have were not actually from a separate species, but rather, just outlier specimens of the same species.And how many outliers of other species have been misidentified as belonging to various proto-humans, too.Without DNA analysis, we're really just guessing. What if they were looking at the fossilized remains of all of today's 300+ breeds of dog, with all the variation those encompass? would they be ID'd as 300 different species??