May 03, 2014

Did Men cause the demise of the Hobbits?

An interesting tidbit from an interview with Chris Stringer:
There was also a population of a very small human-like species on the island of Flores in Indonesia—often called "hobbits." It had been thought they were around until about 17,000 years ago, but unpublished evidence suggests they could have disappeared earlier, in which case the spread of modern humans might correlate with their demise.
and:
My model is that modern humans came out of Africa 60,000 years ago and moved very quickly into the territory of the Neanderthals, later into the territory of the Denisovans, and soon after that into the territory of the "hobbits." Within 20,000 years, as far as we can tell, those other populations have gone, all of them. 

15 comments:

bellbeakerblogger said...

Is it too early to suggest that pygmies might have some hobbit ancestry?

Mark for Summit/Sunnoco said...

The inhabitants of Flores tell a different story- that they killed off the "hobbits" within the last 1,000 years....

Unknown said...

pygmies are no different from you, except that they have a mutation on their growth regulation gene.



terryt said...

"Is it too early to suggest that pygmies might have some hobbit ancestry?"

Certainly not African Pygmies. It is 'possible' the Hobbits may have left genes behind in SE Asia, but even that is doubtful. It will be impossible to know until someone extracts DNA from a Hobbit.

bicicleur said...

I wonder how Flores could remain isolated till 17000 years ago, after all modern humans reached Sahul at least 40000 years ago and the Solomon Isalnds 30000 years ago

terryt said...

@ bicicleur:

"I wonder how Flores could remain isolated till 17000 years ago, after all modern humans reached Sahul at least 40000 years ago and the Solomon Isalnds 30000 years ago"

Chris Stringer said:

"It had been thought they were around until about 17,000 years ago, but unpublished evidence suggests they could have disappeared earlier, in which case the spread of modern humans might correlate with their demise".

However I do remember most dating does suggest they survived until after modern humans had passed by. Perhaps the first people to cross Wallace's Line were adapted to coastal environments and didn't interact with Hobbits for some time. Certainly the first step across the Line seems to have been to Flores, Sumba and Timor before anyone reached Australia,

Unknown said...

It's pretty Darwin to expect isolated populations to tend to specialize and to be more vulnerable to outside pathogens. Mere contact with other humans could have added or subtracted to the "hobbits'" environment and that might have been enough. But the entry of a new type of beetle could have done the same thing

Great speculation from Stringer on Neanderthals:
"Well, even small differences in behavior could have been significant under the stressful conditions that prevailed much of the time for Neanderthals. For instance, we know that modern people had eyed sewing needles in Europe 35,000 years ago. If you have something like that, you can make tailored clothing, or a tent covered with sewn hides, and you get better insulation. You can keep your babies warm more reliably, which is absolutely critical for the survival of the next generation. I'm sure the Neanderthals had some kind of clothing—it would have been essential in Ice Age Europe. But having a sewing needle could make a big difference."

Annie Mouse said...

The people of some parts of Flores (Rampasasa) are remarkably small. I doubt that is a coincidence. I cant see an environmental reason for it so far. Which to me indicates genetic input from the Floresiensis. Whether Floriensis was truly a separate species or a Sapiens variant is yet to be seen (IMO).

http://news.nationalgeographic.com.au/news/2006/08/060821-hobbits_2.html

http://jktmike.livejournal.com/21373.html
(I cant read this, but it has some photos of folk from Rampasasa)

Incidentally there have been reports of pygmies all over South Asia including Australia. They may have been more much more widespread than Flores.

http://quadrant.org.au/opinion/history-wars/2002/06/the-extinction-of-the-australian-pygmies/

Tom Bridgeland said...

If they used a sufficiently different way of life from modern humans, they could have survived, since they wouldn't be in direct competition. Like orangs and chimps which don't directly compete with us for food, and live in areas that support few humans. We seem to have eliminated all direct competition pretty swiftly.
Also, the hobbits may have looked different enough that they were not viewed as 'people', so there would have been no pressure for a pogrom. Nobody hates orangutans for example, because they are just animals. If hobbits were not dangerous to humans, and were so different that they were ignored, they could have survived indefinitely.

andrew said...

@ Annie Mouse.

Insular dwarfism is a well documented phenomena in many species including the elephants living (or at least living at a time contemporaneous with H. Florensis) on Flores itself.

"Whether Floriensis was truly a separate species or a Sapiens variant is yet to be seen (IMO)."

To many skeletal features in Hobbits are archaic in a manner outside the range of modern human variation. You don't see such extreme variations in African Pygmies or in Asian Negrito populations. A Spaiens variant hypothesis is contradicted by the evidence.

@ Mark for Summit/Sunnoco

I personally find that accounts of hobbits living on Flores in small relict populations until the last thousand years to be more credible than the proposition that hobbits died out more than 17 kya around the time of first contact with modern humans (something that linguistic evidence also weakly suggests), although the population may have taken a hit then. Absence of evidence, especially for something as hard to find as this, is not evidence of absence.

I also largely agree with terryt's response to bicicleur, although I think that a simple hypothesis of minimal coastal-inland contact between modern human pro-Melanesians ca. 40kya+ and Hobbits is not the most likely scenario, although the dichotomy may have had some relevance. I suspect instead that there was sustained peaceful co-existence with some economic exchange between the two groups. This may have arisen from a combination of the fact that the founding population of Melanesians may have been pretty small at first contact (and wouldn't have had exposure to animal husbandry related or dog domestication related diseases to replay the modern biological warfare events at first contact), and the fact that the proto-Melanesians didn't feel threatened by Hobbits and thus didn't feel a need to destroy them (I don't agree with Tom Bridgeland, however, that the lack of necessity for pogrom would have had to have extended to seeing them as animals. In local legends the characteristic is more along the lines of child-like, easily tricked fae or "little people" similar to those of European fairy tales) In accord with Tom Bridgeland, A coastal-inland dynamic with the proto-Melanesians having a deep water fishing based means of subsistence as a significant part of their diet as demonstrated with contemporaneous archaeology may have also reduced the incentive to compete rather than cooperate in the area of food production.

@ bellbeakerblogger

We know from hard data that some African pgymies (primarily the more Western of the two communities whose ethnic name escapes me) have a small percentage of archaic hominin ancestry that is neither Neanderthal nor Denisovan, while indigenous people from beyond the Wallace line have Neanderthal and Denisovan ancestry but lack the archaic hominin ancestry found in African Pygmies. The case that Hobbits are the source of Denisovan ancestry in modern humans seems to be a strong one circumstantially, and the case that the archaic ancestry in African Pygmies is from the H. Florensis is virtually nil. But, even if hobbits were not the source of Denisovan DNA, the source of African Pygmy archaic ancestry appears to be African specific and does not appear to be found in Eurasians.

terryt said...

" The case that Hobbits are the source of Denisovan ancestry in modern humans seems to be a strong one circumstantially"

I agree with most of Andrew's comments but I don't think this is the explanation here. The first modern humans to cross Wallace's Line, whether Papuan-like of Aboriginal-like, had presumably spent some time confined to Sundaland. Flores is not part of that 'continent'.

If (and it's a big if) 'Denisovan' equates with Homo heidelbergensis then we can place heidelbergensis' arrival in SE Asia to the time of the change from H. erectus to H. soloensis, about 150-550,000 years ago:

http://en.wikipedia.org/wiki/Solo_Man

Homo erectus seems to have reached Flores some 800,000 years ago:

http://www.athenapub.com/flores.htm

Presumably the Hobbits evolved from these ancient erectus people. That means they had no Homo heidelbergensis input. And the Papuans received their Denisovan element from SE Asian H. soloensis.

Rokus said...

@Andrew,
'To many skeletal features in Hobbits are archaic in a manner outside the range of modern human variation.'

The same argument was wielded against interbreeding with Neanderthal. Still, it was also noted that later Neanderthal converged with certain features of modern human anatomy. The other way round, some highly derived facial features of Neanderthal can nowadays be found virtually all over the world and actually became common modern human markers. Yes, such markers may be missing in the Hobbit: they really had an ape-like nose, not unlike even Australopithecus. However, since modern humans are a mixture, this may be explained as mosaic evolution. Actually, the facial plaster reconstruction of the Hobbit doesn't diverge so much from the small, square people having a flat nose still living in the neighborhood. I don't know any phenotype in the world that is so similar as the people of Ambon that make up a minority in the Netherlands. The other way round again, though mixture with Floriensis may have been less international that with Neanderthal, some modern features can also be recognized in this subspecies. The debate on the Hobbit being actually a modern having microphaly, that I don't agree with, may illustrate this mixture of modern and archaic features. NO DOUBT that some degree of regional gene flow was endemic even here, at this remote and isolated part of the world.

Its funny that even now with ample evidence of archaic admixture of various sources, interbreeding between each and every hominid subspecies continues to be the battlefield of some. What is the gain by excluding "the Hobbit" from the list of subspecies that were able to interbreed with modern humans? Probably it's just another vestige of the Out of Africa paradigm, that dicates that modern humans are the result of a single evolving lineage rather than the hybrid Hotchpotch of archaic mixture. Apparently any evidence of hybridization is perceived as threatening to this emotional presumption.

andrew said...

@terryt

I was not familiar with the evidence of H. Erectus on Flores ca. 800kya. This surprises me and is obviously relevant, although I don't know that it changes the bottom line conclusion much. It can be accommodated a proto-Hobbits replace H. Erectus, or proto-Hobbits fill a void after H. Erectus go extinct in Flores model, in lieu of a Hobbits evolve from H. Erectus model.

I think we are on the same page in concluding that whatever species Denisovan admixture represents, that it probably does not represent H. Erectus, because the TMRCA data for Denisovan DNA relative to Neanderthal DNA and modern human DNA is too recent.

Hu, et al. puts the amount of non-Denisovan and non-Neanderthal archaic admixture with a TMCRA date old enough to be H. Erectus at a very low percentage, with much of it indirect through admixture with Neanderthals who in turn admix with modern humans. There are no known modern human populations with significant spikes in H. Erectus introgression. No more than four archaic homo species with meaningful introgression into modern humans is sufficent to describe all Eurasians, and Africa adds two or three more archaic contributors tops, none of which are shared with Eurasia.

Hobbits are attractive circumstantially, because we have no other archaeologically attested archaic hominin species of unknown genetic ancestry in the right place at the right time to produce the modern Denisovan admixture percentages. Denisovans aren't H. Erectus, aren't modern humans and aren't Neanderthals.

Archaeological exploration isn't as complete in Asia as in East Africa and Europe, but the locations on the geographically mandated path to Flores for any hominin from mainland Asia has had more archaeological exploration than a lot of places. We could have entirely missed a non-Hobbit, non-Erectus hominin species in that vicinity that had peak admixture percentages sometime between 100kya and 40kya, but a story of Hobbits as dwarf Homo heidelbergensis isn't that different from a story of Hobbits as dwarf H. Erectus, particularly given the weakening strength of population continuity hypotheses generally in human pre-history generally as a result of new ancient DNA evidence in multiple circumstances.

terryt said...

" Probably it's just another vestige of the Out of Africa paradigm, that dicates that modern humans are the result of a single evolving lineage rather than the hybrid Hotchpotch of archaic mixture. Apparently any evidence of hybridization is perceived as threatening to this emotional presumption".

I think the single origin of species hypothesis arises from ancient myths, especially from Garden of Eden and Noah's Ark myths in the case of the West. Anything that can be made to fit these myths is immediately jumped on and becomes difficult to dislodge.

"It can be accommodated a proto-Hobbits replace H. Erectus, or proto-Hobbits fill a void after H. Erectus go extinct in Flores model, in lieu of a Hobbits evolve from H. Erectus model".

I still think it most likely that Hobbits evolved from H, erectus on Flores rather than reaching Flores as miniatures already formed. And I don't think anything like H. heidelbergensis reached Flores.

"we have no other archaeologically attested archaic hominin species of unknown genetic ancestry in the right place at the right time to produce the modern Denisovan admixture percentages".

I disagree. Irrespective of Flores we do have ample evidence of archaic humans, or H, erectus, on Java, which was part of Sundaland and so I think the Denisova/heidelbergensis admixture is more likely to derive from Sundaland rather than from Flores.

"We could have entirely missed a non-Hobbit, non-Erectus hominin species in that vicinity that had peak admixture percentages sometime between 100kya and 40kya"

We have an apparent change from full-blown H. erectus to Solo man in Java at the appropriate time. But of course new discoveries will be made.

Ed T. said...

I think that one possible explanation is that we are just more efficient. If two groups have similar cultures, how long before the group that needs less calories to survive dominates?