Posted on 11/20/2002 6:43:45 PM PST by VadeRetro
By Lee Dye
Special to ABCNEWS.com
Nov. 20 — Deep inside a cave in Siberia's Altai Mountains, Christy Turner and his Russian colleagues may have found an answer to a question that has hounded him for more than three decades.
As a young anthropologist, Turner spent time in Alaska's Aleutian Islands in the 1970s, working at several archaeological sites and occasionally gazing westward toward Siberia.
"I thought, 'That's the place that Native Americans came from,' " he says now from his laboratory at Arizona State University in Tempe.
But why, he wondered then as he still wonders today, did it take them so long?
The Bering Land Bridge that the first Americans crossed into the New World from Siberia had been there for thousands of years before those first immigrants arrived, most likely around 12,000 years ago. Archaeological evidence suggests the bridge surfaced repeatedly for at least 40,000 years as seawater became trapped in glaciers during the last Ice Age.
North America was one of the last places on the planet to be populated by humans, and "there has to have been a series of things that kept people out of the New World until very, very late," Turner says.
The evidence he and his colleagues have uncovered, he says, suggests that one player in that drama may have been a most unlikely, and yet terrifying, villain.
The hyena.
Ancient hyenas were larger than their relatives found today in Asia and Africa, and even the modern hyena has a jaw so powerful it can crush the leg of a rhinoceros, Turner says. Modern hyenas tend to be fearless in the presence of humans, and they have been known to drag a human hunter from a tent in Africa and crush his bones like toothpicks.
Could it be that the human migration into the Americas was held up by a nasty beast that preyed on people in the darkness of night, forcing them to remain far south of the land bridge that would have taken them to a new world?
Turner is the first to admit he doesn't know the answer to that. Not enough evidence is in yet to draw any strong conclusions, so at this point this is all scientific theorizing. But the clues so far are tantalizing.
Turner made his first of many expeditions to Siberia in 1979, and as one of the pillars of anthropology in the United States, he has become good friends with many of his counterparts in the former Soviet Union. He has been able to share in their research, including the artifacts they have uncovered in the far North.
"In all of the excavations that my Russian colleagues have been doing across Siberia, they can find almost no human remains," he says. "That's very interesting because if you go anywhere else with an equally good climate, almost always you find a little bit of human bone here and there."
Farther south, at about the latitude of Mongolia, "there are hundreds and hundreds of [human] archaeological sites that go back 50,000 to 60,000 years ago," he says, but just a few degrees north and the sites are no older than 12,000 years.
So Turner began to suspect that perhaps hyenas, running in packs of 40 to 50, may have been intimidating enough to keep those early humans well south of the region where hyenas roamed in great numbers.
Part of the evidence comes from a remarkable cave that was occupied solely by hyenas for about 40,000 years. Turner, who is also a dental anthropologist, examined bones found in the cave and concluded that all of the animals in the cave were dragged there by hyenas.
Most animals gnaw at a bone, or rip it open with slicing molars, but a hyena just crushes it. Even a bear can't do that. The bones found in the cave, Turner says, were clearly there because of the hyenas.
But one set of bones especially intrigues Turner.
"We found a true dog skull," he says. "We've dated the skull to about 14,000 years ago, and it's a domesticated dog," so much smaller than a wolf that it would not have survived if it had not been domesticated. The dog, he adds, was dragged into the cave, where it was devoured by hyenas.
It's the oldest dog ever found in Siberia, Turner says, and it was domesticated just before humans started their migration north, leading them eventually to the Americas.
"The coincidence is so remarkable," he says. "Once we get the dog, then we get people in the new world almost immediately."
Although at this point it's largely guesswork, Turner thinks it's quite possible that those early Siberians domesticated the dog in an effort to protect themselves from hyenas. A dog will bark at anything that approaches its territory, so barking dogs might have helped keep hyenas away from hunting camps.
At the very least, it would have alerted humans to an approaching horde of bone-crushing beasts.
That, Turner theorizes, might have finally given humans the edge, allowing them to encroach further into land thick with hyenas.
Eventually, the humans found the bridge across the Bering Sea, about 2,000 years before the hyenas themselves, along with many other larger animals, died out.
There are many uncertainties and gaps in the archaeological record, because the hyena has been largely ignored by anthropologists, Turner says.
But if he's right, those nasty critters kept us out of here for thousands of years, and dogs finally let us in.
Lee Dye’s column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.
I think it was probably something else, maybe something we can't ever discover through bone fragments. Maybe a religious taboo, or maybe it was simply tales from travelers saying that Alaska was no paradise. But it was something.
I'm not sure what Turner would say. Maybe Mongolia wasn't zoned for hyenas.
I'll try and find some info.
Brought skulls home, their back molars, shoot, their teeth in general are vicious, notably different than dogs.
Being a 5'6, 130 lb. girl who has run across them alone often, I fear them. I'd say 2 could take me down. The guys crossing the Bering were of Mongolian stature, about my size, and if their hyenas were much bigger than the typical 50 lb. coyote, that'd put kinks in my migrating, too.
Thanks for the article. I love pondering the peopling of our continent.
They were obviously intimidated from immigrating to North America by the fiercely nativist, racist Pat Buchanan.
Farther south, at about the latitude of Mongolia, "there are hundreds and hundreds of [human] archaeological sites that go back 50,000 to 60,000 years ago," he says, but just a few degrees north and the sites are no older than 12,000 years.12K years ago was near the beginning of the last/current inter-glacial period. If Siberia is cold now, what was it like during the glacial period?
It may not have been just the hyenas. You need it cold enough to keep a lot of ice in the glaciers, exposing the land bridge. But you can't have it so cold that you can't get from Mongolia across Siberia to the land bridge.
think how incredibly brave or desperate you would have to be to make such a trip.
I hunt and study arrowheads/artifacts, and I wonder if the strata of the 50-60K yo sites show that projectiles/spears were in use 24K-36K years ago. Supposing there were hyenas, big-ass bears and all patrolling the land bridge, humans might want to migrate there, possibly (correctly!) envisioning warmer climactic conditions. Packs of 40 hyena could only be handled with spears, at a distance, no mano y mano would work.
Put another way, maybe the hold-up was due to lack of throwable weapons and an efficient offensive hunting mentality??
The prospect of 50,000 years of hyena progeny in a single cave awes me. Wow. Wonder if we can find a photo of that.
Out of Africa and into Asia
Bernard Wood and Alan Turner
Few doubt that Africa was the birthplace of the hominid lineage, but there is no equivalent consensus about when hominids first moved out of that continent. Despite the announcement of early dates for a juvenile Homo erectus from Indonesia1, the circumstances surrounding the recovery of many of the fossil hominids from the island will always hinder attempts to date them. Thus the excavation of hominid remains, in combination with crudely fashioned artefacts in what are claimed to be early Pleistocene deposits at Longgupo Cave in central China (Huang and co-workers, page 275 of this issue2), is of major importance. Most notably, the remains lend support to the idea3 that representatives of the hominid lineage were established in mainland Asia as early as about 1.9 million years (Myr) ago.
Africa has been the focus for research into human evolutionary history for the past three decades, but it was not always thus. A century ago, space in the correspondence column of Nature was regularly claimed to debate the significance of the finds Eugene Dubois had made, eginning in 1891, at Trinil in Indonesia. Although initially allocated to Pithecanthropus erectus, the species distinction of the Trinil hominid has survived but the genus has long since been sunk into Homo.
Two decades later, excavations were instigated by the Canadian anatomist Davidson Black in the cave deposits at Choukoutien, now called Zhoukoudian, and the first of the series of remains of what became known as ‘Peking Man’ was discovered. Despite being allocated to a new genus and species, their affinities with the hominids from Trinil, and with similar material that was subsequently recovered at Sangiran, also in Indonesia, was evident, and the Chinese remains have also been subsumed within H. erectus. There have been sporadic attempts to demonstrate both that the hominid remains from the Indonesian sites are from more than one species4,5,and that they include specimens that should be allocated to Australopithecus6 or Paranthropus7, and thus to an earlier, more primitive phase of hominid evolution. But none of these claims has survived close scrutiny8. Likewise, until recently there has been little compelling evidence to suggest that any of the Asian hominid sites were yielding hominids more than one million years old3.
The importance of the material from Longgupo Cave is twofold. Not only does it support an early date for the hominid occupation of Asia, but the morphological details of the admittedly fragmentary fossil evidence also means that it may represent not H. erectus but a more primitive species akin to H. ergaster, thus far known only from Africa.
Of course, dating the material is crucial to the argument. Longgupo Cave has several lines of evidence, none of them contradictory. Paleomagnetic stratigraphy shows a reversed polarity for most of the sediments, with the hominid fossils and lithic items associated with the lower of two normal events and therefore referred to the Olduvai magnetic event. The magnetic evidence is broadly supported by analysis of tooth enamel from the sediments, using electron spin resonance, which gives a minimum age of 0.75 ± 0.09 Myr based on an early uranium uptake model. It could be argued that the normal magnetic event associated with the material is therefore likely to be Jaramillo, but the associated mammalian fauna is really too archaic and point instead to the earlier Olduvai event. Of particular interest here is the presence of Nestoritherium, a genus of the family Chalicotheriidae, an extinct, bizarre, claw-hoofed member of the Perissodactyla, today represented by tapirs, rhinos and horses.
The lithic items identified as primitive stone tools do seem to be exotic, and they are notably larger than the rest of the sediments. They look as much like stone tools as anything of this age ever does, and they fall into the category of items in finer sediment deposits that, as Gamble9 has pointed out, tend to categorize genuine archaeological assemblages as opposed to naturally bashed stones. Moreover, the uneroded state of the bone in clay facies channels is consistent with primary deposition rather than intrusive burial. But we are unlikely to be dealing with a site of hominid occupation. The giant hyaena, Pachycrocuta, is a perfectly plausible agent of accumulation10 (it is less likely that the sabre-toothed Homotherium did much bone destroying).
The authors draw attention to the presence of Gigantopithecus, a large, gorilla-like and presumably herbivorous primate, in the same level as the hominid fossils, and stress that this is the third such co-occurrence at Asian localities over a time span of some 1 Myr. Such co-occurrences are always intriguing, but the evidence of hyaena activity reduces the likelihood that Gigantopithecus was prey to the more advanced hominid. The remaining elements of the mammalian fauna at Longgupo shed little light on the local environment of the site, although both woodland and more open-country taxa seem to be represented.
The hominid remains -- part of the left side of an adult mandible and an isolated upper incisor -- are meagre pickings froma taxonomic point of view. However, the mandibular fragment includes both the crown and the root of a premolar tooth (P4), and they provide the best evidence about the affinities of the material. The crowns of the P4 teeth of H. erectus are generally relatively simple and the teeth are usually single-rooted, like those of modern humans. In contrast, the Longgupo P4 root is bifid for most of its length. This, and other features of the mandible and the dentition, suggest that the Longgupo hominid may be much more primitive than H. erectus11. This opens up the possibility that the first hominid to leave Africa was at least as primitive as H. ergaster12, and implies that H. erectus may have evolved within Asia and then spread back into Europe and Africa.
In terms of overall patters of mamalian movement, there is nothing inherently implausible about the age of the material and the implications that it holds for human dispersions from Africa. Hominid remains and lithic items from Dmanisi13 in Georgia point to at least an initial presence at the gates of Europe by around the same time as the age of the Longgupo evidence. And it is clear that a Late Pliocene dispersion across Arabia, probably via the Levant, and perhaps through the Bab-el-Mandab straits, was possible for several mammalian taxa14,15, while the presence of hominids in the Levant itself by 1.4 Myr ago is evident at the Israeli site of ‘Ubeidiya14. The new report from Huang et al. adds weight to other, less well-substantiated claims that hominids travelled even further, and occupied China in the latest Pleistocene some 1.9 Myr ago.
The evidence from Longgupo Cave in China, described by Huang et al.2 and discussed here, suggests that hominids were established in Asia just after two million years ago. Given the primitive nature of the premolar teeth, it seems that the first hominid to occupy Asia may not have been Homo erectus, but perhaps a variant of H. ergaster or even H. habilis.
Bernard Wood and Alan Turner are in the Department of Human Anatomy and Biology, The University of Liverpool, PO Box 147, Liverpool L69 3BX, UK.
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