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Thursday, August 12, 2010

Lucy's knives

New evidence in form of unmistakable stone-tools' marks on bone, push back the earliest known systematic use of tools to an species that was surely not still "human" (in the sense of belonging to the genus Homo) but to Australopithecus afarensis or another similar (but unknown) species. This happened some 3.4 million years ago in the central-northern Ethiopian highlands.

Australopithecus afarensis, the species to which the famous fossil Lucy belonged to, is the only hominin species known to have lived in that space-time. However until now it was commonplace to think that they were vegetarians and did not use tools.

It seems now that such ideas were wrong and that Lucy's species, with a brain barely larger than that of a chimpanzee, was already using not just random rocks but sharp ones able to cut meat. Forensic analysis leaves no room to doubt the marks are product of cutting tools and not animal fangs or paws.

This has potentially interesting implications for the evolutionary history of human brain and intelligence, as well as our highly precise hand, both tightly associated to tool use.

More detailed news stories at Science Daily and BBC.

Ref. Shannon P. McPherron et al., Evidence for stone-tool-assisted consumption of animal tissues before 3.39 million years ago at Dikika, Ethiopia. Nature, 2010. Pay per view.


terryt said...

I don't know if you've seen Kambiz's post at He seems convinced that the marks were made by crocodiles. I'm not yet convinced one way or the other, but if Australopithecus; well, that would be very interesting.

Maju said...

It is, more specifically this link. Your link redirects to a French fashion online shop.

"I don't know if you've seen Kambiz's post"...

Not till now. I was sleeping when he posted.

I don't know what to make of that: if you follow the links posted by Kambiz, I reach to a very brief note, rather than an article, that ends with a "más en español" (more in Spanish) extension link and when you go there it does not say anything either other than the "official" Science version.

Furthermore, the photos of the paper, which seem the only evidence against, actually seem to show very different patterns for the images at the left (ancient) and right (modern experimental by crocodile). Crocodiles marks are much deeper, thicker and, crucially, irregular, with lots of curves and radii. You don't see the V and X patterns anywhere in the croc's chew. I do not think that the marks to the left look crocodile-made at all, sorry.