Human ancestors go back as far as 6 million years , fossilsshow . the genus homo arose at least 1 . 8 million years ago , scientistsbelieve , when australopithecines likely evolved intohumanancestors known as homo habilis , which had larger brains butnevergrew larger than a 12 - year - old child of today 報(bào)道說(shuō),施瓦茲和來(lái)自美國(guó)北伊利諾伊大學(xué)的丹蓋博用各種原始人類的踝骨與現(xiàn)代大猩猩黑猩猩以及人類的踝骨進(jìn)行了比較。