The Great Divide

by Peter Watson

  Despite this, many people would have pressed on to the south, when the prairies, steppes and plains would have been reached and where humans first came across many other mega-mammals, who preferred warmer weather and all of whom had never been hunted before, and some of whom did not exist in the Old World (thirty-five original genera of mammals had shrunk to eight at this point).30

  Geological studies show that, about fifty million years ago, in the era known as the Eocene, Europe and America were joined by a land bridge, probably through Greenland. As a result several large mammals, including an ancestor of the horse and a primitive hoofed mammal, the Coryphodon, existed on both continents. After that, the continents separated and their fauna began to evolve in different ways. At the end of the Eocene, Asia and America were contiguous and animals started to arrive in North America via Beringia which, as we have seen, from time to time was comprised of land. This is when elephants, mammoth and mastodons migrated into what would become the New World.31

  South America was a separate continent from North America until about two million years ago, when the Panama isthmus was formed, and although the two landmasses were close, and some species island-hopped between the two, South America developed its own very distinctive fauna, which included the edentates (sloths, glyptodonts – with bone body-armour, like massive tortoises – and armadillos) and liptoterns (horse-like creatures). At two million years ago, the continents were joined and gave rise to the so-called ‘Great Interchange’, when animals from the north spread south, and vice versa. Thanks to the La Brea tar pit excavations (a cluster of asphalt tar pits, stretching over more than a hundred acres, which formed tens of thousands of years ago in what is now downtown Los Angeles), we know what animals were around when man arrived in the New World. The tar pits were often covered in water, and up to sixty species of ancient animal came to drink. Some fell in and sank into the tar, which preserved them. They date to somewhere between 40,000 and 25,000 years ago and comprise ‘a quite breathtaking disproportionate over-abundance’ of carnivores, which make up more than 90 per cent of the La Brea contents, mostly wolves but closely followed by sabre-toothed cats, lion, sloths, tapirs, bison and bobcats.32 There was also a large number of day-flying birds of prey, attracted by the carcasses in the asphalt, the most spectacular of which was Teratornis meeriami, which had a wingspan of nearly four metres.

  The sheer variety, novelty and size of these mammals and carnivores was one unusual aspect of the landscape into which early man was drawn on his arrival in the New World. None of these creatures had seen man – or been hunted by him – before. Another unusual phenomenon was the relative speed with which, at around this time, the megafauna disappeared.

  This disappearance, and the reasons for it, comprise another of those controversies which beset palaeontology, archaeology and anthropology and, perhaps, are destined always to do so, since the phenomenon under consideration occurred so long ago and where, as a result, the hard evidence is invariably less than adequate. In what follows, it is as well to bear in mind the remarks of Thomas Dillehay, professor of anthropology at Vanderbilt University, in Nashville, Tennessee, who reminded us in 2001 that ‘only one reliable skeleton of late Pleistocene age has been excavated in South America, and only two have been recovered in North America’, making all conclusions and general-isations unusually tentative.33*

  The paucity of early skeletal remains in the New World is puzzling because it is in marked contrast to both the Old World and the Australian experience. We know of only one deliberately meaningful burial before the era known as the Early Archaic period (10000– 9000 BP). A few other bones have been found but they are fragmentary, their contexts are ambiguous and they have rarely been carbon-dated adequately: although some of the early dating produced sensational results (e.g., 70000 BP), these have not been confirmed and, according to later studies, only one is earlier than 10600 BP. The rest come in at between 10200 and 7000 BP.36

  In the Old World in strong contrast, well-defined burial practices and rituals are common after ~50000 BP. Even among the Neanderthal people in Eurasia (~60000 BP), ritual burials were common, it being not unknown for archaeologists to find dedicatory offerings of flowers, exotic flints, red ochre and other materials in what were clearly carefully prepared graves. Moreover, similar burial patterns are seen among the early peoples of Australia. Archaeological remains suggest that this continent was peopled some time between ~70000 and ~40000 BP, with individual and group burials, associated with ritual and grave offerings dated to between ~30000 and 10000 BP. Timothy Flannery makes the point that, despite being settled earlier than the New World, Australia has provided much more evidence of that settlement than have the Americas. He interprets this as vitiating the ideas that America was settled much earlier than the Holocene period.37

  Since ritual burials are so common, so early, throughout Europe, Asia and in Australia – certainly from around 40000 BP onwards – it is more than a little puzzling that we do not find more Ice Age remains in the New World. Are palaeontologists looking in the wrong places? Has there been interference with the sites? Are the radiocarbon dates still unreliable? Was early man in America so mobile that the lack of burial sites became an adaptive trait – it identified a homeland and that consumed too much social energy? As Dillehay puts it, ‘None of these reasons feels substantial. If [early Americans] were cannibalistic, or cremated bodies, we should still have found something.’38 Andevenif the early humans in the New World were very mobile, some human remains should have been found along known migratory tracks – but they haven’t been. The Neanderthals were just as mobile as the early Americans and yet they left remains. The best Dillehay can offer is that palaeontologists and archaeologists are unfamiliar with early New World burial patterns and so they haven’t recognised that what was left behind are remains. Whatever the reason, the mystery endures.

  LIFE BEYOND THE GLACIERS

  Gary Haynes has given one of the most thoughtful accounts of the first humans to occupy the New World.39 He begins by making the point that they would most likely have been hunters because, with the environment being relatively unstable and constantly changing – certainly in the region of the melting glaciers – it would have been easier to adapt the hunting techniques of one animal species to another than to adapt to different plant species in different environments, plant behaviour (the annual cycle) taking much longer to reveal itself and which would have required a more sedentary lifestyle.

  At one time the evidence for early humans in the New World before ~13000 BP was thin and ambiguous, the picture changing at that date with the appearance of the culture known as Clovis, named for the Blackwater location, near Clovis in New Mexico. The defining characteristic of the Clovis culture was a ‘fluted’ hand-axe, a ‘flute’ in this context being a concave groove running along the centre of the blade, a phenomenon that doesn’t exist in Old World stone hand-axes and the function of which will be discussed shortly.

  In recent years, however, evidence has begun to accumulate showing that the Clovis culture, though it may well have been distinctive, did not represent the oldest human presence in the Americas south of the glaciers. Michael R. Waters and a whole raft of colleagues have identified evidence for the occupation of sites much older than Clovis, from Texas to Florida to California to Pennsylvania, some of which physically underlie the Clovis evidence stratigraphically and extend as far back as 15,500 years ago. At the same time Waters and his team have revised the dates for the Clovis era as ranging from ~13,250 to ~12,800 years ago, a span of ~450 years, possibly less. Several sites in South America have yielded radiocarbon dates that are synchronous with Clovis – in Argentina and Chile for example. Waters says it would probably have taken 600–1,000 years for people to travel this far from the ice-free corridor.

  In another study, Jon Erlandson and a team from the University of Oregon found a cache of finely crafted spearheads on the Californian Channel Islands (more than seven kilometres off the mainland) alongside mo
re than fifty shell middens dating back mostly 12,000 years and in some cases to 13,000 ± 200 years. These delicate barbed points, possibly used only in water, are very different from those found at Clovis sites, though Clovis-like flutes were also found on the islands, implying that different groups coexisted and traded at that early time. Also found were pieces of ochre and obsidian, the latter mined in quarries in eastern California, more than 300 kilometres away. Besides showing that these ancient Californians were capable of seafaring, Erlandson says the discoveries confirm that Clovis could not have been the first New World presence, and may be evidence for a coastal migration of early peoples following a ‘kelp highway’.

  Waters says the evidence is consistent with two models. In one, because the Clovis technology seems to have appeared synchronously across the United States, there could have been a rapid spread of Clovis people over an empty continent, with migrants exiting the ice-free corridor and spreading across the contiguous United States in as little as 100 years. The ice-free corridor was navigable at least 200 years before the oldest known Clovis sites and the stone technology of the Nenana culture was well established at the Broken Mammoth site, in Alaska, at least a hundred years before that (Waters finds that the Nenana complex shows ‘strong similarities’ to the Clovis assemblage). The alternative model, supported by the most recent evidence, is that Clovis technology spread rapidly across North America through a preexisting but culturally and genetically undefined human population.

  The earliest identifiable cultures in Alaska, as mentioned, are not Clovis. The first arrivals made blades (not microblades) and unifacial points (i.e., polished on one side only, with one flat surface) that did not have flutes. We know from their remains that these peoples hunted large mammals such as wapiti (or elk, a species of deer) and bison and they also ate small mammals and birds, such as swans, geese, duck, ptarmigan and fish. But they seem to have given rise to two traditions, one being the Denali (microblade) complex, referred to earlier, which derives from Dyukhtai in north-eastern Asia, and could be a specific adaptation to conditions in the Denali area; the second is the Nenana tradition of macroblades, which boasted various forms of stone tools, unfluted but similar overall, as noted above, to what would be elaborated later among the Clovis hunters and foragers.

  Haynes says that ‘thousands of fluted points’ have been found in every region of North America. Fluting, he says, was developed to solve a hafting problem and was so successful that it spread rapidly throughout the continent. He further says that the people who made these fluted points also shared other significant traits: (1) they did not establish year-round camps; (2) they did not accumulate debris-middens as seen in the Old World sites of the same time period; (3) they did not create rock art or in most cases leave artwork in camps (some art has been found but it is ‘negligible’); (4) they were highly mobile; (5) they did not manufacture artefacts needed to process plant foods or fish or smaller mammals; (6) they may have actively killed – or scavenged – mammoths or mastodons more than any other large mammal.40 Timothy Flannery says that flutes may have served another purpose, namely to allow animals to bleed more freely and therefore die more quickly.41 Thomas Dillehay says fluting appeared in South America around 13000 BP.42

  Clovis people preferred larger animals, rather than plants or small-game foods, because big game is more readily located, is not so susceptible to environmental change – say drought – as are plants, for example, and mega-mammals can be tracked more easily without what Haynes called the ‘arcane’ special knowledge needed to find and process non-toxic plants.43 Moreover, he says, the Clovis period is unique in New World prehistory in that ‘never again is the archaeological record for so many different parts of the continent so similar’.44 The dates of the many sites fall within the 15000 BP–10000 BP range and this may be one ‘isolable’ range, or several – the evidence is not sufficient to arrive at a final conclusion. Nonetheless, Haynes believes, unlike Waters, that the ‘Clovis florescence’ began after 13000 BP and that it was over by 11600 BP.45

  The pre-Clovis sites, on both sides of the Bering Strait, are very sparse, very few and contain very small amounts of recognisable arte-facts, so that the evidence for mammoth-hunting in North East Asia and Siberia is ‘at best very scarce and at worst non-existent’ (although it has been so poorly studied that evidence supporting large-mammal hunting could still turn up). Against this background, the relatively rapid appearance of fluted points all over unglaciated North America at around 13000 BP suggests therefore that this was a highly successful adaptation to a new situation that early humans encountered as they emerged beyond the southern edges of the great melting glaciers. At that date, says Haynes, the population of North America stood at ‘not much more than’ 25,000, possibly a thousand groups of twenty-five to thirty each.46

  According to David G. Anderson and colleagues at the University of Tennessee, Knoxville, in a 1998 study, some 12,000 fluted points had so far been reported across the continent, somewhat less than have been found for post-Clovis dates. Judging by what has been excavated where, they say that not more than about 30,000 points of this kind will ever be found, which would give an estimated population for the entire continent of barely one million people, split into 30,000+ separate groups of about twenty-five people each.47 From the distribution of the fluted points, other scholars have suggested that a group of, say, a hundred people (macrobands) may have foraged across areas of approximately 20,000 square kilometres, and may have had ‘staging centres’, where people congregated from time to time after dispersing along the main rivers. Some areas have more fluted points than others, especially in eastern (more wooded) locations (rather than the plains), suggesting that they passed through certain areas without settling them. One estimate is that the early settlers moved on by 250 kilometres each generation and that the morphology of the points changed every ~250 years. If these figures are correct, the rise in population, from 25,000 to 1 million, is a measure of the success of the ‘fluting’ adaptation.48

  Other rhythms that have been discerned in the remains of Clovis and post-Clovis people are that great cyclical movements overlapped the serial patterns, as people returned to quarries and refuges, meaning that quality tools were carried long distances and selectively ‘cached’. Quality stone points have been found as far as 1,800 kilometres from where they were mined, and sometimes attached to them are substances interpreted as ‘hafting cement’.49

  Since the invention of fluting by Clovis people was so successful, and unique to the New World, the question naturally arises as to why this technique was adopted. Here too we meet yet another controversy. It is a notable feature of the Clovis era that, during this time, the large mammals that existed in North America at about 13000 BP disappeared ‘for ever’ within a few hundred years. We know this because a mega-mammal landscape is set across a number of familiar trails and fixed resource points (such as watering holes, coppices), because areas of vegetation are affected by feeding and trampling, because the water holes themselves are enlarged and deepened by wallowing, and because dung beetles feed on the droppings of mega-mammals and spread with them. Within a few hundred years, this type of landscape disappears. Michael Waters and his team confirm that ‘The extinction of mammoths and mastodons coincides with the main florescence of Clovis’.

  Furthermore, as S.A. Ahler and P.R. Geib, at the University of North Arizona, Flagstaff, demonstrated in 2000, the culture which followed Clovis, known as Folsom, named after a site of that name, also in New Mexico, also has fluting but it is subtly different, with more stable hafting and a more uniform configuration, suggesting that these later points were used for only one species of big game – the bison – whereas the Clovis flutes, with their greater variety of shapes, meant these people ‘had fewer worries about access to raw materials’, their points being used with a much large range of creatures.50

  Although it would be natural to expect the Clovis culture to begin either in the ice-free corridor, or immediatel
y south of the glaciers, Haynes argues to the contrary, for it beginning near the present-day Mexican border, because it was a prime mammoth habitat, and where the intense cold would have been a distant memory. He says that Clovis people would have been small – among modern foragers small stature and slow growth are ‘adaptive’ because ‘small babies are easier to carry’ when people have to walk a lot. And others have noted how, among the !Kung foragers in Africa today, shorter men are more successful hunters than are taller men.51 The lack of archaeological evidence for houses meant that the Clovis people moved on from any one site within a month, more or less. And there is no evidence for the use of fire among them. Fire was used extensively in later times – clearing brush makes animals easier to find, removes dead vegetation and encourages new growth, which attracts animals. It can also be used to encircle creatures, it can make travel easier and is a form of communication. But in all these cases, we should see signs of ‘fire-driven mosaics’ of vegetation overlaying the climate-driven and mega-mammal-driven patterns, together with abundant charcoal. But none of this has been observed.

  WERE THE MEGA-MAMMALS SLAUGHTERED TO EXTINCTION?

  After ~11600 BP the configuration of points breaks up into several different forms – not just Folsom but ‘Midland’, ‘Agate Basin’, ‘Plain-view’ and others. Haynes therefore agrees with Paul Martin, of the University of Arizona, who was the first to argue, in 1984, that Clovis hunters had used their exceptionally efficient fluted points to hunt the North American mammals to extinction, mammals which had allowed themselves to be outmanoeuvred because they had evolved in a landscape without people, and were therefore exceptionally tame.52

  This theory has been criticised, not least by R. Dale Guthrie at the University of Alaska at Fairbanks who, in a 2006 paper in Nature, provided new radiocarbon dates for many ancient remains, showing that some species of large mammal, including bison, wapiti and to a lesser extent moose, actually showed an increase in numbers before and during human colonisation of the New World. As Guthrie put it, there was no ‘blitzkrieg’ of mega-mammals; the impact of humans on their new habitat was more subtle.