Tuesday, August 21, 2012


Zomia shown in an intermediate scope definition that includes Tibet and Northern India as well as the core Southeast Asian highland area. "The exact boundaries of Zomia differ among scholars: all would include the highlands of north Indochina (north Vietnam and all Laos), Thailand, the Shan Hills of northern Burma, and the mountains of Southwest China, others extend the region as far West as Tibet, north India, Pakistan, and Afghanistan." (Text and illustration credit to Wikipedia.)

My attention is directed towards Zomia today, of course, because the oldest skull in Asia (outside the Near East) that definitively identified as modern human and also definitively dated (63,000 years old) was recently found in the northern mountains of Laos (a country that is entirely within Zomia).

Zomia, rather than being the land of Zombies, is the geographic region that includes the highland that are between separate India and China, and are bounded on the South by coastal Southeast Asia:

Zomia is a geographical term coined in 2002 by historian Willem van Schendel of the University of Amsterdam to refer to the huge massif of mainland Southeast Asia that has historically been beyond the control of governments based in the population centers of the lowlands. . . . The name is from Zomi, a term for highlander common to several related Tibeto-Burman languages spoken in the India-Bangladesh-Burma border area.

These areas share a common elevated, rugged terrain, and have been the home of ethnic minorities that have preserved their local cultures by residing far from state control and influence. Other scholars have used the term to discuss the similar ways that Southeast Asian governments have handled minority groups.

The region covers more than 2.5 million square kilometers known as the “Southeast Asian Massif” and comprises nearly one hundred million marginal peoples. This large area is inside the fringe of nine states and at the middle of none, stretching across the standard regional designations (South Asia, East Asia, and Southeast Asia) . . . . It . . . [is] an original entity of study . . . a different way in which to study regions.

[According to Professor James C. Scott,] the tribes in Zomia are conscious refugees from modernity itself, choosing to live in more primitive, locally-based economies. . . .

[Hill tribes] seen from the valley kingdoms as “our living ancestors,” “what we were like before we discovered wet-rice cultivation, Buddhism, and civilization” [are on the contrary] best understood as runaway, fugitive, maroon communities who have, over the course of two millennia, been fleeing the oppressions of state-making projects in the valleys — slavery, conscription, taxes, corvĂ©e labor, epidemics, and warfare.

Scott goes on to add that Zomia is the biggest remaining area of Earth whose inhabitants have not been completely absorbed by nation-states, although that time is coming to an end. Though Zomia is exceptionally diverse linguistically, the languages spoken in the hills are distinct from those spoken in the plains. Kinship structures, at least formally, also distinguish the hills from the lowlands. Hill societies do produce “a surplus”, but they do not use that surplus to support kings and monks. Distinction of status and wealth abound in the hills, as in the valleys. The difference is that in the valleys they tend to be enduring, while in the hills they are both unstable and geographically confined. . . .

Southeast Asian expert Victor Lieberman agrees that the highland people crafted their own social worlds in response to the political and natural environments that they encountered, . . . [but] argues that Scott is overestimating the importance of manpower as a determinant in military success. While the bulk of Scott’s argument lies on the efforts of lowland states to dominate the highlands, Lieberman shows the importance of maritime commerce as an equally contributing factor. . . . Lieberman, however, argues that the highland peoples of Borneo/Kalimantan had virtually the same cultural characteristics as the Zomians, such as the proliferation of local languages and swidden cultivation, which were all developed without a lowland predatory state.

Zomia As A Divider Between Geographic Regions

From the perspective of someone whose primary interest is studying population genetics, historical linguistics, ecology, and hominin prehistory and ancient history, the concept of Zomia is also a useful way to help understand why there are natural geographic clusters in Asia in genetics, language, politics and ecology between South Asia, Southeast Asia, and East Asia, respectively. The highlands of Zomia separate them and by discouraging long distance travel, prevent culturally and genetic exchange. Mountains, jungles, deserts and even modest open water distances were some of the main forces to divide populations in prehistory, while river basins and to a lesser extent, open plains or undivided mesas tended to unite them.

Zomia As A Classic Refugium

Zomia shares important social, political, cultural and linguistic similarities with other highland refugia around the world such as the Caucusas Mountains, the Alps, the Mountains near the Volga River which are home to the Mountain Mari people, the Altai, the Nuba Mountain area, the Himalayas, Tibet and the Tarim Basin, the Papuan Highlands, and perhaps isolated areas of Anatolia and Persia.

These regions are often highly balkanized politically and linguistically, are often home to relict populations and cultures that have more effectively resisted assimilation by low land populations, are characterized ecologically by distinctive species of flora and fauna restricted to microenvironmental niches, and often have different food producing methods than the low lands often involving either pastoralism or different kinds of farming than the types found in the lowlands.

In the early Neolithic era in Mesopotamia, the oldest available historical record of these interactions, the herders lived in the nearby hills, while the farmers lived in the lowland river valleys.

The archaeological evidence and one of several theories advanced by classical Roman historians, while not entirely unequivocal, tends to show that the linguistically non-Indo-European language speaking Etruscan people of hilly central Italy derived from an Alpine population described as Rhaetic (although not related except by the area in which it was spoken to the modern language in Switzerland known as Rhaetic). According the their own histories of the ancient Rhaetic people were a relict population that made their way to an Alpine refugium from the South of France fleeing from the Gauls.

Zomia is no doubt home to histories, not widely known in the West (and certainly not well known to me) of similar patterns of highland-lowland interaction and of similarly exiled or relict populations.

Zomia and Mesolithic Expansion Into Asia

One interesting possibility in the Out of Africa and Paleolithic era, is that the more ecologically flexible modern humans, rather than taking a coastal route, may have skirted around archaic hominins like Neanderthals and Homo Erectus as previously supposed, may have been more or less confined to lowland areas by their less flexible subsistence patterns.

One plausible way to test this hypothesis would be to look at a detailed distribution of archaeological evidence such as pre-Out of Africa stone tools in Mousterian and Aterian lithic traditions, and, of course, the detailed geographic distribution of archaic hominin skeletal remains. Large area summary maps often interpolate a hominin species or tool culture's range over a broad geographic area. But, if all actual archaic hominin relic and remain finds are actually confined to lowlands, at least until the appearance of modern humans in the area forced them to flee, then the hypothesis that these species were not "naturally" found in highlands would be supported.

The range confinement of archaic hominins mostly to relatively low altitude environments would seem to be consistent with an apparent absence of arachic hominins in arctic or near arctic climate regions in Scandinavia and northern Sibera. This may have had a very simple explanation. In order to live someplace that gets really cold for long periods of time, you need to be able to build decent semi-permanent shelters (at least away from places where there are naturally occuring caves) and decent clothing. It doesn't appear that either Neanderthals or other Eurasian archaic hominins had this level of architectural and sartorial sophistication. These highlands may have also been ill suited to a subsistence pattern centered around hunting herds of big game like mammoths that may have preferred wide open spaces to tight mountain terrains.

Modern humans may have only ventured further into archaic hominin territory at opportune moments when archaic hominin populations were struggling, perhaps due to shifts in climate or major disasters like volcanic eruptions that were disruptive and caused population decline even if those climate shifts and eruptions in the absence of competition from another hominin species, weren't themselves sufficient to cause them to go extinct. In addition to the pull factor of an increasingly lightly populated fertile destination, modern humans at these times of climate change and/or disaster triggered effects may have faced the push factor of an increasingly inhospitable territory that encouraged them to seek greener pastures despite the presence of some existing hominins occupying that territory.

Zomia and the Distribution of Y-DNA Haplogroup D

The Mesolithic Southern Mountain route "into Asia" scenario described above could provide one way to reconcile the disconnect between Y-DNA haplogroup D. Y-DNA haplogroup D is very old on a mutation dated basis, and has a patchwork mountainous and island distribution that is seemingly suggestive of a previously wider distribution, but is very thinly present outside of the refugium areas where it is found. One would expect a once widely distributed first wave population to leave more of a genetic substrate trace in lowland areas. One would also expect a first wave modern human population in Southeast Asia to have some level of Denisovian admixture, which, in fact, Y-DNA haplogroup D carriers uniformly lack.

The analysis above offers an alternate hypothesis to the theory that Y-DNA haplogroup D carriers were a second migration wave (a hypothesis consistent with its distribution, but not its mutation rate dated antiquity) that could explain the pattern of Denisovian admixture, could be that archaic hominins in Southeast Asia and East (probably all descended from Homo Erectus) without an absolute genocide on the mainland that produced no hybrid descendants outside mainland Asia. Archaic hominins in Asia may have characteristically fled from incoming modern human populations, rather than sticking around to admix as Neanderthals apparently did, until they ultimately reached a final dead end in some Denisovian caves from which they had no further route of retreat.

In this scenario, modern traces of Denisovian admixture are confined to populations of Island Southeast Asia because the archaic hominins on these islands, lacking reliable means of maritime transportation at that time, had no ability to flee incoming modern humans and once forced to co-exist with the newcomers, admixed to a signficant extent with them.

How did this happen?

Perhaps the original distribution of the Y-DNA haplogroup D people was one designed to avoid archaic hominins, rather than one due to being pushed out by or skirting around different waves of modern human populations. Then, new waves of modern humans swept in to replace archaic hominins in areas where the archaics died out before the people with Y-DNA haplogroup D then quite ensconced in their mountain lifestyle could swoop in and lay claim to the lowlands.

Thus, Y-DNA haplogroup D people may never have co-exististed in close proximity to archaic homins in Asia (after the initial Out of Africa admixture with Neanderthals), and may not have experienced serious population pressure from lowland modern humans until the post-Last Glacial Maximum era.

Was Asian Archaic Admixture Influenced By Archaic Hominin IQ?

Commenters at this blog, like Terry, have made the point here and at other blogs, that circumstantial evidence from Neanderthal brain case size, for example, tends to suggest that Neanderthals (who share a common ancestor with modern humans perhaps 800,000 years ago) were comparable in intelligence to modern humans. Populations of species like the Neanderthals with comparable intelligence to modern humans may have felt that they had decent odds of holding their own without fleeing the newcomers into a land to which they had developed more specialized anatomical adaptations. And, indeed, the Neanderthal did not go completely extinct until something on the order of 80,000 years after their first Eurasian contact with modern humans in the Levant, and were the dominant hominin species in Europe for more than 50,000 years after modern humans left Africa, until the Upper Paleolithic revolution took hold in modern humans (roughly coincident with the Aurginacian archaeological culture and the point at which we see evidence of deep sea fishing in Island Southeast Asia and modern humans crossing the Wallace line).

In contrast, known examples of Homo Erectus species had smaller brain cases than either Neanderthals or early modern humans relative to their body size. Their lithic tool cultures in Asia were also even more static than that of the Neanderthals, showing almost no innovations in the archaeological record from the initial arrival of Homo Erectus in Asia around 1,800,000 years ago through the disappearance of this Acheulean tool culture around 100,000 years ago when they too disappeared. This could have been due to the fact that their African tool set was better adapted to their semi-tropical or tropical Asian territory and thus needed no improvement to be optimal, or due to archaic hominin use of bamboo tools in preference to stone tools that left no relics for us to find today.

Map of Range of Archaic Hominin Lithic Tool Cultures. Map source: Wikipedia (recent analysis and an original source map from 2010 found here supports the continued viability of the geographic distinction shown in this map originally proposed in the late 1960s and suggests that that East Asia and Southeast Asian shaded areas represent an independent and more primative development).

But, maybe they were just cognitively incapable of much innovation even relative to Neanderthals whose lithic tool set was much more static and narrow than that of modern humans, at least, by about 75,000 years ago where modern human bone tools, harpoons, and post-Mousterian lithic tools began to appear in the archaeological record (and perhaps any modern human intellectual advantages relative to Neanderthals date only from that time period) (critical analysis of this hypothesis can be found, for example, here). Thus, archaic hominins in Asia may have viewed themselves as more clearly out matched by incoming modern humans making flight in the face of their arrival a more clearly desirable option.

Another, perhaps further reason that there may have been less archaic hominin admixture in mainland Asia relative to areas of modern human co-existence with Neanderthals, may have been that less intelligent archaic hominins in Asia may have seemed like less desirable mates than more intelligence and modern human-like Neanderthals who also had less genetic distance from modern humans.

A Neanderthal admixture event may have seemed to the participants like an extreme case of interracial sex. Admixture with what I have hypothesized were less intelligent Asian archaic hominins may have seemed more like instances of bestality analogous today to sex with a chimpanzee or monkey or oragatang (none of which are popular even within the subculture of pornographic fetish writing). Many modern humans who cohabit with these primates eat them (it is called "bush meat"); none of the modern human populations of which I am aware that cohabit with other primate species have a tradition (even covert or taboo) of sexual relations with primates. Even rampaging lawless soldiers who seem to rape every woman they encounter in places like the recent horrible wars in the Congo, are not known to go about raping females of the primate species they encounter in their travels.

Sunda, Sahul, and the Wallace Line, from Wikipedia

The existence of Homo Flores, the "hobbits" of Flores island, could explain why this is different in Melanesian and Australian Aboriginal populations, whose ancestors almost certain had to pass through Flores en route to Melanesia and Australia. Flores is the third island to the East of the Wallace line, about 40 miles from the Bali which is the eastward most island that was part of mainland Asia during the last glacial maximum, at which point the distance across the Wallace line was about twenty-miles. The next two steps would have been from Lombok and Sumbawa, which is about 8 miles, and between Sumbawa and Flores which is about 12 miles.

The leading explanation of Homo Flores is that they were Homo Erectus individuals who experienced the common phenomena of island dwarfism in their evolution. Intelligence is a function of brain size relative to body size, so evolutionary changes that reduce the body size of a species tend, all other things being equal, to increase its intelligence. Their smaller size would also make them cuter and less threating. It also isn't inconceivable that island dwarfism may have in some way contributed to making it possible for hybrid children to be carried to term.

Mainland Asian archaic hominins at the end point of their trail of exile from a core territory in mainland Southeast Asia and East Asia found in bones in a cave in Denisovia may have been only 100,000 to 200,000 years diverged from Homo Flores and drawn from the same population, so genetically Homo Flores, late mainland Asian Homo Erectus, and the Denisovians whose remains date from a time period when that species would have been moribund (and may perhaps have even hybrid Neanderthal-Erectus individuals in a population that no longer existed as a pure type at that point), would have been no more genetically distinct from each other the most genetically distant clades of modern humans that exist today.

The point at which modern humans crossed the Wallace line, by far the most formidable biogeographic barrier that expanding modern humans had yet encountered, may also have been the moment at which these populations faced their most serious population genetic bottle neck, thus making it possible for a quite small number of instances of admixture with archaic humans to have a maximal effect, and would likewise be a point at which the proto-Melanesians may have had their most dire gender imbalance leaving either men or women as the case might be, short of partners.

Flores as the source of all Denisovian admixture in modern humans is supported because it is the only place where there seems to be some credible archaeological signs that modern humans and archaic hominins were sometimes part of the same community on a sustained basis (with Homo Flores possibly serving as servants in some instances), or at least where the two species appear to have engaged in sustained trade relationships with each other for thousands of years. Homo Flores and modern humans probably co-existed from not later than circa 45,000 years ago until perhaps as late as 12,000 years ago and was probably the last archaic hominin species to go extinct. Thirty-three thousand years of co-existence is a long time, and the extinction of Homo Flores comes not long after the period when the Western islands of Indonesia would have been joined to the mainland as part of the Sunda penninsula, bringing in new peoples and ideas which may have been disruptive to the fragile harmony that modern humans had reached with Homo Florensis there. There are even some linguistic hints that Flores may have had an unexpectly large population of non-native language learners or people with reduced linguistic abilities (perhaps the hobbits) that is not found in the related languages of neighboring islands in Indonesia.

Everywhere else (except possibly in the Levant from the initial arrival of modern humans there about 100,000 years ago until about 75,000 years ago when modern humans disappeared from the region for a couple of dozen millenia), co-existence in one particular geographic location of two separate hominin species appears to have been short lived (probably not more than 1,000 years in any one place; perhaps less, since the fuzziness in dating technologies account for some of the duration of the maximal period of overlap in any given location).

This timing shows some consistency with the timing of the baseline levels of Neanderthal admixture in modern humans which seems to take place at the peak moment of a proto-Eurasian modern human population bottleneck around 75,000 years ago in the Near East. Interspecies admixture may have been something that modern humans intentionally refrained from resorting except in times of extreme shortages of reproductive alternatives during population bottlenecks.

The bottom line is that it isn't inconceivable to me that almost all "Denisovian" admixture in modern humans is actually traceable to a dozen or two instance of admixture with members of the species Homo Flores on the island of Flores, and that a strong flight instinct of Homo Erectus population members who did not experience dwarfism and had someplace to which they could flee, together with a modern human perception of those who did not experience dwarfism as more primate than fellow hominin, could have meant that there was no meaningful amount of archaic hominin admixture anywhere else in Southeast Asia or East Asia (with a possible exception probably involving even fewer instances of admixture relative to the founding population in the Philippines).


terryt said...

"an original source map from 2010 found here supports the continued viability of the geographic distinction shown in this map originally proposed in the late 1960s and suggests that that East Asia and Southeast Asian shaded areas represent an independent and more primative development)"

The line between the two is usually refered to as 'the Movius Line' (in case you didn't know that). Some even believe that the line may represent the demarkation of H. erectus and H. ergaster.

"Flores as the source of all Denisovian admixture in modern humans is supported because it is the only place where there seems to be some credible archaeological signs that modern humans and archaic hominins were sometimes part of the same community on a sustained basis"

I think we will find something very similar in Java though.

Human Genetics Journal said...

Thanks for sharing.