Redating Homo floresiensis and Reconsidering the Genocide Hypothesis

Originally published at Bizarre Zoology on April 2, 2016

floreskull
The Liang Bua cave (LB1) Homo floresiensis individual and the cover of Dr. Jared Diamond’s The Third Chimpanzee (Source; Source)

I have no intention for this blog to act as a regular news source, but I will occasionally cover current zoological issues or findings if I feel that I can offer any sort of valuable commentary. This is an example of a brief news-oriented article. A paper published last Wednesday in Nature titled Revised stratigraphy and chronology for Homo floresiensis at Liang Bua in Indonesia proposes a new date for the diminutive-bodied and small-brained hominins uncovered in 2003. Rather than attempt to summarize the paper, here is the abstract:

Homo floresiensis, a primitive hominin species discovered in Late Pleistocene sediments at Liang Bua (Flores, Indonesia)1, 2, 3, has generated wide interest and scientific debate. A major reason this taxon is controversial is because the H. floresiensis-bearing deposits, which include associated stone artefacts2, 3, 4 and remains of other extinct endemic fauna5, 6, were dated to between about 95 and 12 thousand calendar years (kyr) ago2, 3, 7. These ages suggested that H. floresiensissurvived until long after modern humans reached Australia by ~50 kyr ago8, 9, 10. Here we report new stratigraphic and chronological evidence from Liang Bua that does not support the ages inferred previously for the H. floresiensis holotype (LB1), ~18 thousand calibrated radiocarbon years before present (kyr cal. bp), or the time of last appearance of this species (about 17 or 13–11 kyr cal. bp)1, 2, 3, 7, 11. Instead, the skeletal remains of H. floresiensis and the deposits containing them are dated to between about 100 and 60 kyr ago, whereas stone artefacts attributable to this species range from about 190 to 50 kyr in age. Whether H. floresiensis survived after 50 kyr ago—potentially encountering modern humans on Flores or other hominins dispersing through southeast Asia, such as Denisovans12, 13—is an open question.

Hobbits Without Homo sapiens

Basically, the geological reevaluation conducted by Sutikna et al. (2016 ) rejects the previously inferred date of 12,000 years ago and instead ascertains an age of between 190,000 and 50,000 years ago, one which predates the presence of any Homo sapiens remains in the region. Apart from further refuting the hypothesis that the LB1 skeleton represents a pathological Homo sapiens individual, this revision brings another controversial proposition into question. As the prior date was largely significant in indicating tens of thousands of years of coexistence between Homo floresiensis and Homo sapiens, the press release of this paper has been accompanied by much discussion over how the new findings shape the narrative of interactions with our species. Some of the authors have stated that, as the corrected age for the species’ last appearance no longer coincides with the deadly volcanic eruptions of Flores occurring approximately 12,000 years ago (Dorey 2016), the notion of modern humans having a direct role in the demise of the Flores people may need to be reconsidered. Although the first signs of modern human habitation in Flores date to 11,000 years ago, archeological evidence indicates that Homo sapiens were first moving through southeast Asia and Australia around 50,000 years ago  (Callaway 2016). The correlation between the Flores hominin’s latest occurrence in the fossil record and the initial dispersal of Homo sapiensthrough Australasia has been described as likely more than coincidence by several of the authors (Callaway 2016). However, this is not the first time an extinction sparked by the arrival of modern humans has been proposed in connection with Homo floresiensis. In fact, this very hypothesis appeared in the anthropological literature ten years earlier, in a book which I am currently finishing: biogeographer Dr. Jared Diamond’s The Third Chimpanzee.

The Invaders of Flores?

The Harper Perrenial edition of this book contains an addendum titled “Measuring The Third Chimpanzee Against New Discoveries,” an ingenious addition considering the rapid rate at which findings are being made and challenged in Anthropology. In this section, Diamond comments on the then-breaking discovery of Homo floresiensis and confidently challenges the claims of coexistence. Due to the long history of our species’ genocidal tendencies, Diamond (2003 reissue of the 1992 publication) argues that the Flores people would have been quickly exterminated after their first contact with modern humans, possibly within 100 years of our species’ colonization of the island. He has similarly argued that human xenophobia, pathogens, and technologically-advanced weaponry were the bane of the Neanderthals (Diamond 1992), a hypothesis which I feel can be rejected due to its assumption that there was a rapid extermination event somehow not indicated through injuries inflicted upon skeletal remains or records of the event in Paleolithic cave art. To the contrary, the most recent anthropological consensus asserts that Homo sapiens and Homo neanderthalensis coexisted for a substantial period of time with occasional interbreeding and cultural exchange. However, the new date suggesting that the Flores hominins did not experience a long overlap with Homo sapiens but rather went extinct around the time at which modern humans were first occupying Australasia fits in with Diamond’s notions regarding a violent first contact.

So Much Paleoanthro, So Little Time

So, do the conclusions of the new paper  lend support to Dr. Jared Diamond’s previous writings, and indicate a rapid extinction of Homo floresiensis at the hands of arriving Homo sapiens? It’s an intriguing possibility which I feel deserves further consideration. Plenty of work remains to be done by anthropologists at the Liang Bua site, and more interesting findings regarding Homo floresiensis and its fascinating island ecology (this was a hominin that lived alongside pygmy stegodontid elephants, large tree rats, giant marabou storks, and komodo dragons) are sure to come forth. I would love to discuss at length other noteworthy topics such as the interpretation of the Flores hominins as relic australopithecines, what the age revision means for the associated Ebu Gobo tales (they likely have a sociocultural basis in the universal wildman archetype), and the implications of the reference to Homo sapiens ssp. Denisova in the abstract, but alas time does not currently permit it.

IMG_7642
Yours truly with a replica of the LB1 specimen at the National Museum of Natural History. Note the sign in the background which references the findings of the Nature paper discussed in this article.

References:

Callaway, Ewen. “Did Humans Drive “Hobbit” Species to Extinction?” Scientific American. Nature America, 31 Mar. 2016. Web. 01 Apr. 2016. http://www.scientificamerican.com/article/did-humans-drive-hobbit-species-to-extinction/.

Diamond, Jared M. The Third Chimpanzee: The Evolution and Future of the Human Animal. New York, NY: HarperCollins, 1992. Print.

Dorey, Fran. “Homo Floresiensis.” Australian Museum. Australian Museum 2016, 31 Mar. 2016. Web. 31 Mar. 2016. http://australianmuseum.net.au/homo-floresiensis.

Sutikna, Thomas, Matthew W. Tocheri, Michael J. Morwood, E. Wahyu Saptomo, Jatmiko, Rokus Due Awe, Sri Wasisto, Kira E. Westaway, Maxime Aubert, Bo Li, Jian-Xin Zhao, Michael Storey, Brent V. Alloway, Mike W. Morley, Hanneke J. M. Meijer, Gerrit D. Van Den Bergh, Rainer Grün, Anthony Dosseto, Adam Brumm, William L. Jungers, and Richard G. Roberts. “Revised Stratigraphy and Chronology for Homo Floresiensis at Liang Bua in Indonesia.” Nature (2016): n. pag. Nature Publishing Group. Web. 31 Mar. 2016. http://www.nature.com/nature/journal/vaop/ncurrent/full/nature17179.html.

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