The hobbit is still Homo floresiensis

ResearchBlogging.orgIn 2003 Evolutionary Anthropology came crashing into popular culture with the discovery of Homo floresiensis, found – as the name might suggest – on the island of Flores. Affectionately nicknamed “the Hobbit” by the media, this diminutive creature stood at only 108 cm tall (~3′ 6”) and by virtue of this peculiarity managed to capture the public’s attention.

But being tiny is only scratching the surface of the bizarreness of H. floresiensis. The hobbit made tools on par with the humans of the time, despite having a brain 1/3 their size and lived during a time when all other hominins had died out (except H. sapiens).

Understanding the hobbit would revolutionise how we view human evolution, yet coming to terms with our miniature cousin is something we’ve yet to do. Why is it tiny? How could it make such complex tools? What species did it evolve from?

Did it have furry feet?

One persistent answer to the mystery surrounding the hobbit has been that it isn’t especially mysterious.  Almost as soon as it was categorised as a new species people were arguing that it wasn’t, that it’s actually just a Homo sapiens with some kind of condition.

Microcephaly – a condition in which a person’s head is signficantly smaller than average – was one of the first conditions proposed to explain H. floresiensis since it can produce individuals with a brain size on par with the hobbit. Although this typically greatly impairs intelligence, it would mean that there was a population of modern humans present who could produce the complex tools discovered.

Yet shortly after microcephaly was suggested it was refuted. Cranial scans of sufferers revealed that they had a significantly different brain shape than the hobbit did. Further, although victims of the condition have been known to be short, none have a skeleton similar to those found on Flores.

"For doubting my taxonomy you recieve DEATH GLARE!"

But that was not the end for those who dispute assigning the specimens from Flores to a unique species and in the intervening years they have suggested many other conditions which could explain the existence of the hobbit without drastically altering our understanding of human evolution.

The most recent pathological explanation for H. floresiensis is that they are “myxoedematous endemic cretins.” Now, I must confess that before I started researching this topic I only knew what 1/3 of those words meant: endemic (or “unique” to you lesser, non-sciency mortals).

Drat.

On top of that, even “endemic” has a different definition in the world of pathology.

Double drat.

So I guess it’s time to twirl my moustache and play “catch the definition.”

The operative part of that sentence was "twirl my moustache".

Which was surprisingly easy.

Clinically…[myxoedematous] cretins are usually distinguished by…extreme growth retardation, facial dysmorphism [differences], myxedema [insufficient amounts of thyroid] and less severe mental retardation

Further, clinical definitions typically come with a precise suite of features used to define the condition, allowing us to diagnose the specimens from Flores! Which is exactly what recent research has done, taking the extensive list of features used in the diagnosis of “cretinism” (I’m still not sure if I’m comfortable using that word) and applied them to the hobbits.

The comparison table is very long and the end result of this in-depth comparison? They aren’t alike at all. Other than the short stature, the only skeletal feature Homo floresiensis has with cretins is their humerus is twisted in a similar manner. Pretty much every other feature used to diagnose myxoedematous endemic cretinism is absent.

Rather hilariously, this includes having a normal sized brain! That’s right, the disease being used to explain why there were small-brained, small-bodied hominins on Flores does not result in small brains. Cretinism also results in differently shaped feet and hands, which the hobbit doesn’t have; it also means people keep their milk teeth, which the hobbit didn’t…

And this is just a fragment of a very long table

However, the hobbit skeleton doesn’t look as it would have when it was inside a person, having been altered and damaged by spending thousands of years in the dirt and during excavation. This introduces a potential source of error, since these specimens might only be different because they have been changed by such taphanomic (“after death”) processes.

Claiming that this is the case is one of the arguments put forwards by those suggesting the hobbit is just a cretin, suggesting that the skull size has been reduced hence the discord between the small-brained hobbits and the large-brained human cretins.

For example, they suggest that the skull used to be larger as there was cartilage between the bones, but this decayed and the bones came closer together, eventually fusing into a smaller sized skull.

Such alterations leave behind fingerprints on the bone, so to speak, which can allow this claim to be tested. As one might have guessed by now, it turns out those suggesting the hobbit is a cretin are wrong.

The areas which have undergone deformation don’t seem to align with where bones would merge if cartilage disappeared. On top of that, there are sections of the skull which aren’t deformed but should be if what the pro-cretin crowd say happened happened.

(B) is the hobbit, with areas of deformation highlight in green. The numbers on (C) mark where deformation should be.

So, it would seem the hobbit is still the member of a unique species: Homo floresiensis. Which means the mystery is a mystery again.

For scientists, who love to investigate, this is good news. For those who just want easy answers well…

Triple drat.

Brown, P. (2012). LB1 and LB6 Homo floresiensis are not modern human (Homo sapiens) cretins Journal of Human Evolution, 62 (2), 201-224 DOI: 10.1016/j.jhevol.2011.10.011

30 thoughts on “The hobbit is still Homo floresiensis

  1. A lot of people think that our intellect doesn’t come from brain size, but from a brain size/body size ratio. So I wouldn’t be surprised if smaller people with smaller brains are as smart as us.

    Even so, my two pence:

    1) Genetic disorder not yet discovered in the current populous? (very possible).

    2) Known genetic disorder, which they then evolved from and developed.

    Is this not possible?

    • However, the hobbit had the smallest encephalisation quotient (a figure regarding brain size relative to body size) of any hominin meaning that, compared to other members of our lineage at least, it had a small brain even for it’s body size.

  2. I’m missing the idea of insular dwarfism in your discussion. This has been floated in this connection a lot, though it’s also been debunked partly:

    Meiri, Shai, Natalie Cooper, and Andy Purvis. 2008. “The Island Rule: Made to Be Broken?” Proceedings of the Royal Society B: Biological Sciences 275 (1631) (January 22): 141-148. doi:10.1098/rspb.2007.1056.

    • True, this was not a complete discussion of all possibilities proposed, just a single paper and some relevant side issues. Perhaps I will get around to doing other ideas on day, thank you for the link.

  3. Cretinism, like Laron’s Syndrome, is an absurd diagnosis by folks who have never even seen the fossils they purport to diagnose. Both pathological claims crept into the literature through epic failures of “peer review” and the old boy network.

    Brown’s new paper is devastating for the cretin crowd, and Falk’s earlier paper (American Journal of Physical Anthropology) thoroughly debunked the Laron Syndrome. For a thorough, detailed analysis of the skull of H. floresiensis, check out the recent paper by Kaifu and colleagues in the Journal of Human Evolution; they favor the hypothesis of island dwarfing from a Homo erectus ancestor. It’s plausible, but it requires the unprecedented evolutionary reversal of many characteristics, from brain size to jaw shape to bodily proportions as an unexplained correlate of dwarfing.

    • I do agree that many of the pathological explanations for H. floresiensis are absurd, but I do like the fact that they are being put out there. It forces people claiming the hobbit isn’t the result of some deformity to provide exceptionally robust evidence for their case, like the paper this blog post was commenting on. Since they’re driving research forwards in this manner I will tolerate people making silly claims.

  4. I was surprised that the microcephaly suggestion received as much credibility as it did, albeit briefly. My stepdaughter was a microcephaly victim. Without the intervention of modern medicine her life expectancy was less than 5 years. Apply modern medicine and adulthood was also highly unlikely. Put the little one into a wild human population and I’m afraid her chances of survival would have been considerably less than either scenario.

    • To be fair I think that proponents of the microcephaly explanation also argue there were typical humans around as well. Certainly, some of the tools in the vicinity are quite similar to modern human technology which does lend a bit of credence to the idea. As such I’m not that surprised it was given as an explanation but I am surprised by how long it stuck around. Although there is a bit of evidence for it it doesn’t stand up to much scrutiny and so the hypothesis should’ve been abandoned after a year or so.

  5. In 1996 I lived and worked on the island of Sumatera based in the small village of Gumpang located in the high country southeast of Banda Aceh. My work involved extensive periods of field work in some of the most remote and wild country imaginable. As a safety precaution against the known dangers of tigers and elephants I employed three local men who might best be described as revered bushmen. These three gentlemen assured me of a third dangerous critter they referred to as “orung pendek” or short man. My initial response was one of skepticism but I asked a sequence of questions relating to their sightings that left me believing their stories were not fabricated. The discussion we had was matter-of-fact material about legitimate dangers to be expected. For example, if you meet orang pendek on a walking trail, give way or expect to be damaged as it passes. Orung pendek has enormous upper body strength and a low centre of gravity my guides warned. Are we talking about orung hutan, our mispronounced orangutan I asked but received a negative response. Not to be outdone I asked the head man for a description of an occasion when he encounter orung pendek and the final part of his answer made me believe we were dealing with something real. He was walking along a jungle trail when he heard rustling in the shrubbery. On parting the ferns he saw a female orung pendek giving birth on a laid out bed of leaves. I considered the last bit of information just too elaborate to invent on the spur of the moment. Foolishly it did not occur to me at the time to ask what position she was in. I make two points. I have every reason to believe that these men were genuine and interested only in my safety. Secondly, perhaps there is an argument for reconsidering the past tense “lived” in your second paragraph, that is, maybe we still share time and space with an erectine.

    • They asked some people who had just seen the challenger disaster where they were at the time. When asked several months later where they were only 10% gave an accurate description with a full 25% giving a description that was completely different to the one they had originally given. Eyewitness testimony – particularly when concerning so-called “flashbulb” memories – can easily be wrong simply due to how malleable our memory is. As such I’d like a bit more evidence before I conclude there is a hobbit walking around still.

      • A deft answer Adam. Still, I note that a tropical rainforest is less than a perfect environment in which to find hominid fossils, especially with numerous tigers lurking around, (we had 16 tiger sightings in 3 months). Gumpang might be a reasonable location in which to search for DNA. Apparently there exists in the area a limestone sequence hosting numerous caves that may be worth investigating at some point but I suggest anyone prepared to do so takes heed of the local advice. The name used by the locals to describe this area translates as “condominium of tigers”!

        • Very true, rainforests rarely preserve fossils because of the humidity, which is one of the reasons we have so few chimp fossils is because they spend most of their time in such environments.

  6. Pingback: Who was the hobbits ancestor? « EvoAnth

  7. The hobbit peoples are real one still exist in mountain surrounded thick forest.Holy quran clearly mention their name yaajuj-maajuj.In bible yahog-mahog.as per islam those peole tiny size 3 feet only,good hunter and archerer.they eating everything.They will be come out from the hill during the time of jesus second coming and spoiled the world.The lady hobbit birth more than 1000 children in her life time.This hobbit people one of the adams ancestor.Prophet Mohammed (Pbuh) said this people living in eastern side.May be they are living indonesia thick forest hillside area.

  8. I have read (but don’t know whether or not it really is true) that some people with microcephaly have a fairly normal level of intelligence. If correct, this means that the small brain of the hobbit did not preclude it from having a far greater amount of intelligence than some ‘experts’ imagine it could have had. Thus microcephaly in H. sapiens is a ‘natural experiment’ which demonstrates that a hominid with a small brain could be pretty intelligent, and ‘brain wiring’ rather than size might be the more important component of intelligence… Another point is that if the remains of 9 – 16 (I have seen a wide range quoted) hobbits are known, spanning a time range of 40,000 or so years, yet not a single bone of a ‘normal’ sized Homo sapiens has been discovered amongst them, then the probability that all of these were diseased individuals is so vanishingly small as to be practically impossible. It seems very, very unlikely that a custom of burying microcephalic individuals in a cave could have persisted for such a vast length of time.

    • A very small portion (~7% irrc) of microcephalic individuals have a “normal” level of intelligence. However, it should be noted that we’re still dealing with individuals with a modern brain composition and structure; albeit smaller than normal. We have no way of knowing if the same holds true in a species – like the hobbit – that might have a different distribution of neurons, or differently sized lobes and so forth.

      • Thanks for the additional information. My point is as follows: the fact that some Homo sapiens individuals with microcephaly have ‘normal’ intelligence shows that it is possible for a Homo species with a very small brain to have the level of intelligence of a ‘normal’ H. sapiens. So the argument that the brain of the hobbit was simply too small for it to have been intelligent (as compared to H. sapiens) is rubbish! Whether of not it WAS intelligent is another matter, but it’s evident use of fire and ability to make stone tools strongly suggests it was.

        • Except that we’re talking about two different species in one case and two members of the same species in the other. Gorillas have a brain the same size as some microcephalitic individuals, yet 7% of them do not have human intelligence. Brain size is a rather crude way of trying to figure out intelligence anyway.

          • I think you are missing the point! To say that a species of Homo with a brain the size of the hobbit could not be as intelligent as a ‘normal’ H. sapiens is clearly false, since there are known individuals in the genus Home, which have brains as small as the hobbit, yet which have the intelligence of a ‘normal’ H. sapiens!

            • Again, that’s assuming that the Homo sapiens brain is representative of Homo in general; which it likely isn’t. Neanderthals, for example, had a brain with a significantly different structure to ours. Trying to apply inferences about intelligence from one to the other is thus very tricky. Hence why there is debate over the intelligence of the Neanderthals; despite the fact they have a bigger brain than us.

            • Some scientists believe that intelligence in mammals as a whole can be inferred from relative brain size – e.g. see http://en.wikipedia.org/wiki/Encephalization_quotient My argument was dirrected at this approach.
              Quote “Encephalization Quotient (EQ), or encephalization level is a measure of relative brain size defined as the ratio between actual brain mass and predicted brain mass for an animal of a given size, which is hypothesized to be a rough estimate of the intelligence or cognition of the animal.”

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