The Megafauna Extinction

We have seen above that from approximately 100,000 to 50,000 years ago, anatomically modern humans were confined to Africa, plus the warmer areas of Europe and Asia. After that, our species underwent a massive geographical expansion that took us to Australia and New Guinea around 50,000 to 60,000 years ago, then to Siberia and most of North and South America, and finally to most of the world's oceanic islands only around 2000 bce.41 We also underwent a massive expansion in numbers, from perhaps a few million people 50,000 years ago to about 150 million around 2000 bce.42

Our capacity as a social species to transform nature dramatically increased during this early phase in human social evolution due to the development of language and the associated expansion of our symbolic and social organizational capacities. This crucial turning point in the biological and social evolution of the human species essentially marks the continuation of biological evolution by cultural means. It is precisely at this conjuncture that humans begin to pose a global environmental risk. The cultural and geographic implications of this profound evolutionary transformation are first manifest in what Jared Diamond refers to as the "Great Leap Forward" - that is, our species' terrestrial expansion to and colonization of all major ecosystems, and the accelerated evolution of technological and artistic innovations.43 This was soon followed by the development of gardening and farming, and, 10,000 years ago, by the emergence of sedentary agriculture. The invention of metallurgy and use of metal tools arose around 6,000 years ago.

Human-animal relationships changed dramatically. Surpassing our archaic predecessors anatomically and behaviorally, modern humans of the late Pleistocene acquired unprecedented skill as big game hunters.44 The impressive testimony of these changes is manifest in the leitmotivs of the flourishing cave art. Leopards and hyenas, hitherto unknown in Paleolithic cave art, were depicted in conjunction with images of lions, rhinos, bears, owls, mammoths, bison, ice-age horses, Irish elk, and extinct deer with giant antlers.45

Homo sapiens developed a keen understanding of their new prey. As a food historian suggests, big game hunting was history's first, but not last, "war on subsistence."46 New technologies and socially expanded intelligence became manifest in newly created material culture and ingeniously designed weaponry for catching prey including such instruments as harpoons, fish gorges, bows and arrows, spear throwers, pit traps, dead falls, blals, and arrow poison.47 These devices and more tightly coordinated hunting techniques must have considerably increased food supplies. Homo sapiens were now socially coordinated enough to collectively dismember and carry away the remains of large mammals such as great mastodons and woolly mammoths. They were able to encircle great numbers of animals and drive them over a cliff. This enormous wastefulness in hunting was to become a chief characteristic of anatomically and behaviorally modern humans' attitude toward their food supplies.

Indeed, the extermination of the megafauna in the late Pleistocene should be taken as the first indicator of the greatly expanded transformative capacities of modern humans on the planet's species and ecosystems.48 The term "megafauna" refers mainly to large herbivores such as mammoths, mastodons, huge ground sloths, cave bears, and woolly rhinoceros, as well as the carnivores that fed on them, such as dire wolves and saber-toothed cats. This pre-industrial form of ecocide represents a prelude to what was to evolve, under the aegis of the modern industrial era, into a collectively species-threatening pattern of global ecocide. The human-induced megafauna extinctions of the late Quaternary occurred in many different parts of the world, and involved at least 200 genera.49

For example, at Solutre, France, at the bottom of a cliff used by ice-age big game hunters to massacre stampeding animals, one can find a vast accumulation of bones estimated to contain the remains of more than 100,000 horses.50 Even allowing for the relatively vast time period of the Paleolithic or Old Stone Age, it seems obvious that these ancient hunters killed more game than was necessary.51 In the Pacific Northwest, pre-modern people created elaborate devices to drive herds of white-tailed deer into enclosures in the forest where they were slaughtered. Native American people have been recorded to have burned forests to force out elk and deer, creating gusts of hot wind, soot, and smoke powerful enough to make temperate October days feel like mid-summer. On the Great Plains, some tribes drove bison over cliffs, creating heaps of fur and meat far greater than their needs. Mounds of remains, discovered by archaeologists at the foot of cliffs, show that the animals were left to rot.52 There is also evidence from bones that before Bison antiquus became extinct, the species suffered stress, which may well have been caused by overhunting.

The megafauna mass extinction of the late Quaternary is now generally acknowledged by paleontologists and physical anthropologists to have occurred largely without the impact of global catastrophes such as sudden climatic change.53 In most cases, the megafauna extinctions began shortly after the first arrival of prehistoric humans. If we compare the number of genera of large mammals lost on the various continents, we find that Australia lost 94 per cent, North America 73 per cent, Europe 29 per cent, and Africa south of the Sahara 5 per cent.54 The first humans encountered animals that had evolved in the absence of human predators, and the animals were probably easily vanquished. Therefore, the most plausible explanation is that these extinctions were caused over the course of centuries and millennia by over-exploitation of relatively few, but growing numbers of big game hunters. Let us examine these extinctions in several geographical regions.

In Africa, early humans were not as carnivorous as their descendants in other parts of the world were. However, it is now well documented that more recent accelerated extinctions in Africa did coincide with the rise of advanced, early anatomically and behaviorally modern human Stone Age hunting cultures. Africa lost its giant buffalo, giant wildebeest, and the hipparion, a giant horse. Although Africa still has more large animals than any other place on Earth, even there, the megafauna that we see today is only about 70 per cent of the genera that were present in mid-Pleistocene. About 50 genera disappeared about 40,000 years ago.55

In Eurasia, there is good evidence that the megafauna extinctions occurred a few thousand years earlier, with most animals becoming extinct about 12,000 to 14,000 years ago.56 Late Pleistocene megafauna in Europe included the woolly mammoth, woolly rhinoceros, musk ox, giant deer (the "Irish elk"), bear, bison, and the cave lion. Many of these species became completely extinct. In the case of extinction patterns in Southern Europe, it has been pointed out that all the large fauna of the Mediterranean disappeared soon after human arrival between 4,000 and 10,000 years ago. Most scholars agree that the megafauna extinctions in Europe were mainly due to "the over-extension of human hunting after major changes had taken place in the prey population."57

The arrival of humans in Australia resulted in the extinction of most of the large animals on this continent. Australia lost all of its very large mammals, including marsupial mammals much larger than present ones, such as giant wombats as big as grizzly bears and giant kangaroos. Lost, too, were Australia's giant snakes and reptiles, and half of its large flightless birds.58 About 85 per cent of the Australian animals weighing more than 100 pounds disappeared.59 Humans burned vast areas of the outback, a practice that proved to be extremely destructive for what was then already a rather fragile and dry environment.60 According to paleobiologist Tim Flannery, Australia's original inhabitants were the world's first group to over-exploit their environmental resources. Australian aborigines eliminated 95 per cent of their continent's large mammals by about 20,000 bce, long before the onset of the most recent ice age.61

On the islands of Aotearoa (New Zealand), the situation was only nominally different. Here, large flightless birds dominated the megafauna and anthropogenic extinction of species is a much more recent affair, beginning about 1,200 years ago. Again, humans were clearly responsible.62 But not only birds such as the giant Moa, flightless wrens and small petrels suffered range reductions or extinctions in the prehistoric era. Other affected species included sea mammals, reptiles, amphibians, insects, and, to a lesser extent, fish, molluscs, and crustacea.63 The zoological impoverishment of the region followed soon after, after a second wave of social colonization, with European whaling and sealing leading to widespread environmental degradation from the North Island to the furthermost South.

Of all continents, the megafauna mass extinction data are clearest for North America, where 70 species (95 per cent of the megafauna) disappeared about 11,000 to 14,000 years ago. This is exactly the time when North America was colonized by humans, and their arrival and skill as hunters at that time are documented by the appearance of artifacts.64 In some cases, accurate dating methods have shown that certain species became extinct at exactly the times that humans arrived.65 Giant ground sloths and mountain goats in the Grand Canyon both went extinct 11,100 years ago, the same time that human hunters arrived. The mammals that disappeared in North and South America included all of the following: mammoths, mastodons, various kinds of horses, tapirs, camels, four-horned antelopes, ground sloths, peccaries, giant beavers, dire wolves, giant jaguars, and saber-toothed tigers.66 The carnivores on the list were probably not hunted directly, but, as they were dependent on the large herbivores for food, they followed them to extinction. South America was also colonized by humans about 11,000 years ago, and since that time it has lost 80 per cent of its genera of large mammals, including ground sloths, horses, and mastodons.67

In the Pacific islands there is no reasonable doubt that the arrival of humans caused megafauna and, in particular, bird extinctions.68 For example, archaeologist team Storrs Olson and Helen James argued that of the 68 endemic Hawaiian birds, 44 became extinct before they could be recorded by ornithologists.69 The coincidence of timing of extinction with first human arrival is equally convincing for Madagascar and for the Caribbean.70 Madagascar has yielded subfossil bones of giant lemurs and elephant birds and cow-sized hippos. The island is believed to have been settled by humans only recently, around 500 CE, and all these species were apparently extinct by the time that Europeans began describing Madagascar's animals in the seventeenth century. In the case of the Caribbean, it is important to note that, until first human colonization, as early as 7,000 years ago, Cuba and the other islands that constitute the Greater Antilles were home to a number of mammals found nowhere else. In Cuba they ranged in size from the island's behemoth, a ground-living sloth, estimated at 400 pounds, to monkeys71 as large as any living in the forests of Brazil today. Among the other large vertebrates were enormous, flightless owls, giant tortoises, and monk seals. Except for a few fragments, this part of the megafauna is gone.72 No one has ever tried to guess the number of plants, invertebrates, and lizards exterminated by prehistoric human habitat destruction.73

Still, the impact of our species on late Pleistocene ecosystems was rather small in many ways, compared to our cataclysmic social ecological impact in the modern era. Calculations suggest that a mere 20,000 humans lived in France around 30,000 bce in Neanderthal times. The pre-European population of the Americas during this period has been estimated at something less than 1 million, and the human population of the Australasian continent was probably between 300,000 and 600,000.74 All in all, there were not more than 5 million to 10 million humans in the whole world. The evolutionary playground or setting and locale of Homo sapiens during the Old Stone Age, in one scholar's description, was "a human desert swarming with game."75 People still predominantly lived by hunting and foraging, but a lot of land was needed to support a tribal group or clan or family.

The progressively detrimental impact of Homo sapiens and the global expansion into previously uninhabited habitats is, therefore, historically a very recent and unprecedented phenomenon. Before moving into a more elaborate discussion of humanity's more recent ecocidal activities, I wish to re-emphasize the pivotal role of language in the evolutionary odyssey of humans.

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