Was "Lucy" Human or Ape?

One place the two of you might enjoy discussing is her ideas on Lucy. She argues on her website that Lucy was fully human. This is outside mainstream, but not by much. Part of the problem is that we don’t really have a good definition of “human”, but setting that aside, there seems to be a lot of substance here to discuss.

This seems to be an old page, so @Alice_Linsley might be expected to update her argument with new facts here too if she likes.

A recent discovery of a complete fourth metatarsal of A. afarensis at Hadar shows the deep, flat base and tarsal facets that “imply that its midfoot had no ape-like midtarsal break. These features show that the A. afarensis foot was functionally like that of modern humans.” (Carol Ward, William H. Kimbel, Donald C. Johanson, Feb. 2011) Read the report here.

Additionally, A. afarensis apparently used polished bone tools, shared food (which apes don’t do) and used fire. Some of the earliest evidence of controlled use of fire by humans was found at Swartkrans in South Africa. Other sites that indicate fire use include Chesowanja near Lake Baringo, Koobi Fora and Olorgesailie in Kenya.

A. Afarensis also had human dentition which is quite easily distinguished from that of apes. In humans, the back teeth are larger than the front teeth (not so with apes), and the canines are not pointed. Humans also lack the characteristic diastema or tooth gap found in apes.

Mary Leakey’s 1979 discoveries in Tanzania added to the evidence that humans walked the earth about over 3 million years ago. At Laetoli, about 25 miles south of Olduvai Gorge in Tanzania, Leakey discovered footprints of a man, woman and child created about 3.6 million years ago and preserved under falling ash from the nearby Sadiman volcano. The raised arch and rounded heel of the footprints showed that whoever left these footprints walked as humans today.

Unfortunately, Donald C. Johanson had already announced to the world that the Australopithecus afarensis were apes, though Mary Leakey would have classified her Laetoli finds as Homo/human. She expressed her regret that “the Laetoli fellow is now doomed to be called Australopithecus afarensis.”

Johanson and Mary Leakey were scheduled to speak at a Nobel Symposium in Sweden in May 1978. The conference honored Mary Leakey, who received a medal from the King of Sweden for her scientific investigations. Mary Leakey received the Golden Linnaean Medal, but also was very embarrassed when Johanson announced the new name - Australopithecus afarensis - for his Afar Triangle finds and included Mary Leakey’s 4 million year old Laetoli specimen (jaw bone LH4) from Tanzania as an exhibit.

Johanson, who was scheduled to speak before Mary Leakey, scooped Mary’s speech. She was angry that Johanson had named her discoveries, using a designation that was totally at odds with what she believed to be the evidence. Johanson’s name stuck though he clearly has doubts based on more recent discoveries as to the accuracy of the ape designation.

The designation of the finds in Ethiopia as apes is contradicted by the evidence that these fossils had oppositional thumbs, short fingers, human dentition, and apparently built fires. Discoveries in Dikika, near Gona and Bouri, Ethiopia indicate that they shared their food, and used flints to scrap, saw and chop. Two fossilized bones have been found that appear to be marked by stone tools. On the basis of low-power microscopic and environmental scanning electron microscope observations, these bones show unambiguous stone-tool cut marks for flesh removal and to access bone marrow.

The evidence taken together indicates that Lucy and her community were human, though not modern humans. What do you think?

I notice an interesting subtext of gender here that is most certainly important. For a very long time, women have not been treated fairly in science. Given how arbitrary the distinctions here are between Homo and not-Homo (to this non expert and to experts too: What is the Genus Homo?), I would not be surprised if gender-bias was part of the story.

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Can anyone independently verify these parts of the story?

I want to know if this is a true story.

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I’d say that that’s the whole problem and we can’t set it aside because it’s the nub of the question. I think the entire discussion is pointless. One could try to restate the question in terms that actually have meaning, but that would make it a very different question.


I think it is difficult to define “human” without being arbitrary. For example, some of the human-like physical features in A. afarensis were listed, but there are also many features that are ape-like, such as the large brow ridges, prognathus, sloped forehead, conical chest, and so on. At some point it is like trying to draw a line between cold and hot or young and old.


Well, for one thing you can’t name a new taxon in a speech. It requires a published, formal description. A name announced in a speech can’t “stick”. It might even pre-empt the name, which would then be considered a nomen nudum, though I’m not sure about that.

This is the actual description: Johanson, White & Coppens 1978. A new species of the genus Australopithecus (Primates: Hominidae) from the Pliocene of eastern Africa. Kirtlandia, No. 28 1978: 1-14.

Also, anyone is free to transfer the species to the genus Homo. There is no rule that would have prevented Mary Leakey or anyone else from making that change; it’s just a matter of whether particular other scientists accept either designation.

Finally, the name A. afarensis applies directly only to the type specimen, presumably Lucy, and anyone is free to add or remove other specimens to/from the species as they see fit. Again, whether others agree is the important thing.

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Does any one know the history of taxonomic assignment of Lucy?

Can anyone educate me here? What are the key features that anthropologists look at? How are they distributed?

No detail is “trivial” when investigating the culture traits of archaic and ancient human populations.

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To my knowledge, nobody has ever explicitly placed Lucy in any other genus than Australopithecus. A few people have done so implicitly by synonymizing Pan with Homo, but only based on molecular data (foolishly, if you ask me) and never mentioning fossils.

There are no key features that should be relevant. “Human” has no scientific meaning, and Homo is a phylogenetically defined taxon, not one based on particular characters.

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Genus Australopithecus goes back to Leakey’s discoveries in the 1960’s. When Donald Johanson
discovered Lucy in 1974, it was much older than other Australopithecus at 3.2 million years ago. He named Lucy’s species Australopithecus afarensis

7 posts were split to a new topic: Robert Byers Learns About Gender Bias

Where to draw the line between and around genera has always intrigued me. I am not aware of any hard and fast rules for what a genus is, but perhaps there are. Looking at it objectively, if there can be thousands of species in the genus Drosophila why couldn’t there be 3 living species in the genus Homo (humans, chimps, bonobos)? I would suspect that there is more genetic distance between species within Drosophila than there is between humans and chimps, so what’s the deal?

There are not. Genera are supposed to be monophyletic, though Australopithecus seems to be an exception even to that. A few people have tried to use genetic distance as a criterion, but they can’t agree on numbers, and there are probably single species that would be split into multiple genera if any of the proposed numbers were agreed on.

There’s nothing particularly wrong with putting Pan within Homo, but there’s nothing particularly right with it either. Taxonomic ranks are all arbitrary, with the exception of the species, for which there are moderately clear criteria.

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I don’t know how reliable this reference is, but it looks decent:

That would seem to exclude Australopithecus. I also like the fact that Linnaeus is the type specimen for Homo sapiens. This is the definition for H. sapiens, but the globular cranial vault and the reduced supraorbital ridges fit with other Homo species.