Hobbits are back, and they’re REAL!

I’ve written quite a bit about the Homo floresiensis controversy: these are the small (1-meter tall) individuals whose remains were found in a cave on the Indonesian island of Flores, originally dated about 18,000 years old.  They are remarkable because of their size, their small brains (about the size of a chimp’s) and their remarkably recent age — a time when the much taller and brainier Homo sapiens had already infested the world.  But there was doubt about whether these diminuitive fossils represented a real species: some people thought that the one relatively complete skull represented a diseased or microcephalic individual.

Two papers in the latest issue of Nature (links below) address this controversy, and both come down on the side of H. floresiensis being a real species, not an aberration. (There’s also a very nice two-page summary by Daniel Lieberman if you don’t want to plow through the articles.)  More bones have been found in the Liang Bua cave on Flores (see below), most notably a pretty complete foot.  The foot, like the rest of the skeleton, shows an intriguing mixture of primitive and derived traits.  There are now enough bones to pretty much rule out the “aberrant individual” theory.

So what was H. floresiensis?  As the diagram below shows, it could have been a descendant of an earlier hominin species, H. habilis, or perhaps a very early form of H. erectus; in both cases it would have had to reach the island several million years ago.  Yet the brains of these two ancestors were larger than that of the hobbit, so how did it get such a small titer of gray matter? (Hobbit brains were about 400 cc in volume, the size of a modern chimp or of the smallest australopithecines.)  Here the notable dwarfism of many species on islands (including elephants on Flores) comes in: like other mammal species, H. floresiensis could simply be an evolutionarily dwarfed form of an earlier hominin. Weston and Lister’s paper gives relevant data taken, oddly enough, from dwarf hippos on Madagascar , but I’ll leave you to follow their reasoning in their article.

This is perhaps the most bizarre and interesting twist in hominin evolution yet, and it’s completely unsettled.  A whole new group of questions open up.   How did this weird species coexist with the much larger and brainier H. sapiens for so long?  (H. floresiensis was not dumb, by the way: they managed to colonize the island over water and made fairly sophisticated tools).  If hobbits are a remnant of the H. habilis lineage, how come we don’t find habilis fossils elsewhere outside of Africa?

The foot of Homo floresiensis.   W. L. Jungers, W. E. H. Harcourt-Smith, R. E. Wunderlich, M. W. Tocheri, S. G. Larson, T. Sutikna, Rhokus Awe Due & M. J. Morwood

Insular dwarfism in hippos and a model for brain size reduction in Homo floresiensis. E. M. Weston and A. M. Lister

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Ling Bua cave on Flores: where the hobbits were found.  Photograph by C. Turney, University of Wollongong

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Homo floresiensis might be most closely related to early H. erectus, but also shows potential affinities with H. habilis. In either case, recognizing H. floresiensis as a species will require us to re-examine how we define species of the genus Homo and how they were related to each other. Reasonably well-known relationships are indicated by solid arrows; less secure relationships are indicated by dotted arrows. Broken vertical bars indicate uncertainties about when species evolved or went extinct. (Figure and caption from Lieberman’s summary.)

7 thoughts on “Hobbits are back, and they’re REAL!

  1. How did this weird species coexist with the much larger and brainier H. sapiens for so long?

    Well, it worked in Bree-land.

  2. They likely kept to themselves. If I lived next to a tribe of giants I’d do my best to stay clear of them.

  3. Anyone any idea as to why there has been such resistance to Homo Flores being identified as a separate species?. It seemed fairly obvious it was, based on the wrist bones, but the microcephaly hypothesis has been very persistent.

  4. The phylogeny looks far too linear to me. Surely, we haven’t captured so many ancestor-descendant relationships!

  5. This may seem a bit wacky in re. this, but it finally got me to look up the relationship between Downy and Hairy woodpeckers. I don’t consider myself a birder, but I do enjoy feeding them in the winter, and in the course of that I’ve finally been able to notice that they distinctly differ in size.

    (By contrast, my mother was a birder and used to get excited when she’d see a Hairy (the larger of the two). At the time I couldn’t tell any difference, and I think most people would fall into this category. Unless you’re used to looking at them with the same thing as reference (for me, my suet feeder), they look very much the same, at least in the Eastern US.

    Anyway, if you find your way to the Wikipedia pages on the two, it turns out that they are now believed, on the basis of mitochondrial DNA, to be an example of convergent evolution. I got no sense that there was any prior thought based on bone structure or that sort of thing that they were in different genera, but that is apparently what has come from the DNA work.
    So, from this, until/unless some DNA is forthcoming from the hobbits, it might be wise to withhold falling into one or another camp on the relationships.

  6. and they’re REAL!

    Really?

    They may have found a foot, but I saw no mention of it being hairy.

  7. Very cool story.
    It has been fun watching it evolve.
    I’m glad I stumbled on to this blog – good info. thanks.

    It’s awesome trying to imagine the world H. floresiensis knew.

    The idea that they could be H. habilis holdouts from that fantastic early migration of a hand full of disgruntled tribes in search of new horizons.

    And they held out on their isolated island(s)an extra few hundreds of thousands of years – talk about the ultimate survivors.

    Keep up the blog.

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