The discovery of the supposedly 1.8 million-year-old hand axe in Lenggong, Perak (see previous postings in this blog) has generated a lot of interest among the archaeological circle worldwide. The reason being, if the hand axe is indeed as old as it is claimed to be, then the Out-of Africa ancient human migration model will be seriously put to question.
First and foremost, in order to avoid confusion, the Out-of-Africa theory could be used to refer to two separate ancient human migration. The first one refers to the migration of Homo erectus out of Africa, about 2 million years ago, to populate the rest of the Old World as evidenced by findings of Homo erectus remains in Georgia (1.8 million years ago); Jawa, Indonesia (1.7 to 1.2 million years ago); as well as Longgupo and Yuanmou in China (1.8 to 1.6 million years ago).
According to the second one, referred to as the Recent Out-of-Africa model, anatomically modern Homo sapiens evolved in Africa, and migrated into Eurasia and the rest of the Old World about 200,000 years ago, and along the way, completely replaced (without interbreeding) the older human populations.
The Out-of-Africa theory that is being challenged by the recent discovery in Malaysia is specifically the first one. According to Dr. Mokthar Saidin, quoted in a New Strait Times article (“Rewriting Out-of-Africa Theory” 30 Jan, 09), Homo erectus in Jawa, Indonesia could have migrated from Bukit Bunuh in Lenggong, Perak (Malaysia) as a result of destruction from the impact of meteorites. A model tentatively proposed to challenge the Out-of-Africa model is the Out-of-Southeast Asia model. I don’t buy this completely. Does this new model propose that Homo erectus evolved in Southeast Asia and then migrated to populate the rest of the world? At this time, there is no evidence to support this. Africa, after all, has yielded numerous fossil evidence of “ancestors” of the human species, such as a number of species from the genus Australopithecus, Homo habilis and of course, Homo erectus. Southeast Asia has only produced findings of Homo erectus, and the infamous Homo floresiensis. Also, the Out-of-Africa migration happened earlier than the date of the hand axe found in Lenggong, and based on dates alone, the Out-of-Africa theory still holds. Frankly, there is still not enough evidence to propose a Southeast Asian origin for modern Homo sapiens.
In my opinion, further research needs to be conducted before any conclusions can be made regarding the rewriting of the Out-of-Africa model, as well as to verify the age of the hand axe. At this moment, little is known about the dating methods used to obtained the 1.8 million years ago date of the hand axe.