Fallback Foods and The Diet of Australopithecines

Physorg.Com has an interesting report on new research by Nate Dominy on underground storage units:

In the new paper, entitled “Mechanical Properties of Plant Underground Storage Organs and Implications for Dietary Models of Early Hominins,” Dominy tested USOs, which plants use to store water and carbohydrates. His data establish rhizomes as the toughest, followed by tubers, corms, and bulbs (familiar examples of which include Bermuda grass, potatoes, iris, and onions, respectively). Corms and bulbs emerged as the most plausible hominin foods, according to Dominy, because their physical qualities match up with dietary inferences based on dental morphology and modern chemical isotopic analysis.
The new data also allowed Dominy to correlate plant characteristics with the dental morphology of different species of hominins. The teeth of Australopithecus, for example, appear well-suited to process bulbs, while the teeth of Paranthropus appear well-adapted to process hard and brittle corms.

The paper is supposed to be published in Evolutionary Biology but I haven’t been able to track it down.

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6 Responses

  1. There was a good summary of the above research in “Science,” but, like you, I have yet to track down the precise reference. In the meantime, you might want to compare an article in PNAS by Adriana Hernandez-Aguilar et al, Vol. 104, No. 49 (Dec. 4) 2007, pp. 19210-19213, entitled “Savanna chimpanzees use tools to harvest the underground storage organs of plants.” It suggests to me that various hominoids have been digging up and dining on roots and bulbs for a very long time, indeed.
    Then there was “Excavation of a Chimpanzee Stone Tool Site in the African Rainforest” in Science (296)5572: 1452-1455 in the issue May 24, 2002. Chimps have also been cracking open nuts with rocks for thousands of years, something we previously thought only humans and our direct ancestors did. I suppose you already noted the chimps who hunted with “spears”? They are appearing more and more like early humans all the time, aren’t they?
    Now I’ll go hunt for that tooth article.

  2. yeah, I have read both of those already.

  3. While I don’t have the N. Dominy reference, I see, a similar bit of research was done by Matt Sponheimer of the Univ. of Colorado, reported by Ann Gibbons in Science, May 2 2008, Vol. 320, pp. 608-9. He did a carbon isotope study of the teeth of a variety of fossil animals, including gracile and robust australopithecines in South Africa. He discovered that the values on the hominins’ teeth fell between those of other browsers, such as giraffes and antelopes, which ate fruits and soft leaves, on one hand, and of grazers, such as wildebeest and zebras, which ate fibrous grasses and sedges, on the other. His conclusion was that BOTH hominins ate mostly fruit and young or early leaves when they were available, turning to grasses and sedges at other times, like modern baboons. So why did the robust australopiths have those massive jaws? He suggests that they allowed the beasties to eat “fallback” foods like fibrous leaves, during droughts and other times of crisis, rather like modern gorillas. These apes prefer fruits and soft leaves, but will turn to more fibrous leaves and the bark of trees if they have to.
    Peter Ungar also has a couple of articles on diet and dentition, one from 2004, one from 2005, available through ScienceDirect — but you’ve probably seen those too.

  4. Sponheimer has done a number of articles on the subject. Laden and Wrangham, Schoeninger, Perry, and Yeakel have also written on the subject (Yeakel’s paper, which also includes naked mole rats, is particularly cool – co-authored by Dominy). As far as I know, the idea was originally promoted by Wrangham and, independently, by K. Hawkes beginning in the mid-90′s.

  5. I have found another reference to Nathaniel Dominy and his study at http://www.ucsc.edu/news_events/text.asp?pid=2328. It gives a little more detail than Physorg, also mentioning that the original is “published in the online edition of the journal Evolutionary Biology.” Interestingly, this article is dated August 25, 2008, so I suspect that the original is not actually out there yet! That’s probably why we can’t locate it. Another article about Dominy and his work, with a photo of him leaning over a table with a hominin skull on it and a basket of their foods is in the UC Santa Cruz Review, pub. in Fall 2007, written by Jennifer McNulty.

  6. I too can’t find the paper in Evolutionary Biology. But I have come across another new related publication of his in the Journal of Human Evolution, “Food material properties and mandibular load resistance abilities in large-bodied hominoids.” Do you want a copy of the PDF?
    Kambiz

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