years.5 According to a late-2010 study, the decline in tiger numbers ‘has continued unabated’ for the last two decades: only 1,000 breeding females now survive, over less than 7 per cent of their historical range. Several Indian so-called ‘tiger reserves’ no longer have any tigers in them at all. Yet saving the tiger could cost as little as $82 million per year, according to one estimate – this is all it would take to protect the remaining 42 sites around Asia where viable tiger populations remain.6 All that is needed is a mechanism to raise the funds and an implementation plan to safeguard the reserves.
Particularly badly hit by our success have been our nearest relatives, the great apes. All are threatened with extinction in the wild. In Asia the orang-utan – once common from South China to the Himalayas – is now reduced to a remnant of between 45,000 and 69,000 individuals, mostly in the sort of lowland forests in Borneo that seem to be particularly irresistible to oil-palm plantation owners. In Africa the famous ‘gorillas in the mist’ of Virunga National Park in the Congo are down to about 380 individuals, under siege by marauding rebels as well as by poachers and bushmeat hunters. To put humans in our proper context, try entering ‘great apes’ into a www.iucnredlist.org (a website run by the International Union for the Conservation of Nature, featuring its Red List of endangered species) search. When I tried, the results were as follows:
Gorilla beringei (Eastern Gorilla) – Status: Endangered, Pop. trend: decreasing.
Gorilla gorilla (Lowland Gorilla) – Status: Critically Endangered, Pop. trend: decreasing.
Homo sapiens (Human) – Status: Least Concern, Pop. trend: increasing.
Pan paniscus (Gracile Chimpanzee) – Status: Endangered, Pop. trend: decreasing.
Pan troglodytes (Common Chimpanzee) – Status: Endangered, Pop. trend: decreasing.
Pongo abelii (Sumatran Orang-utan) – Status: Critically Endangered, Pop. trend: decreasing
Pongo pygmaeus (Bornean Orang-utan) – Status: Endangered, Pop. trend: decreasing
As this list shows, we are just apes. But with our newfound global power comes a responsibility for proper global stewardship. This is a new task for humans to take on, certainly at a planetary level. But the time for this shift is long overdue, for a brief review of our history to date shows us in a very singular role: that of serial killers.
THE PLEISTOCENE OVERKILL
Many thousands of years ago a dramatic ecological calamity began to sweep through the fauna that inhabited the Earth’s disparate continents. Australia lost most of its large animals first, about 46,000 years ago. North and South America saw a similar extinction wave 13,000 years ago. New Zealand, meanwhile, kept hold of its big-bodied animals until a mere 700 years ago. What happened at each of these points in time? Did the climate perhaps change, leaving large animals stranded? Unlikely: there is no correlation between global climate change and the various extinction pulses. Did a meteor strike or a volcano blow? Again, there is no way to pin all of these different calamities, taking place at very different times, on a single geological event. Indeed, the true nature of this extinction calamity is much more familiar. It came on two legs, for a start. What links these points in time is simple: they mark the moment when humans arrived.
Modern humans have at least dealt out death fairly: we began our existence by killing each other. In what looks like a prehistoric bout of all-too-modern ethnic cleansing, Homo sapiens probably drove its closest hominid relatives, Homo neanderthalensis and Homo erectus, to oblivion. A minority of archaeologists cling to the notion that some interbreeding must have taken place, but genetic studies show this is unlikely.7 Modern human DNA instead confirms that all of us are descended from the same small initial Homo sapiens population that migrated out of Africa 50,000 years ago.8 The last Neanderthals hung on in remote mountainous parts of France until 38,000 years ago, and in southern Spain until about 30,000 years ago. The very last families died a few thousand years later in Gorham’s Cave in what is now Gibraltar, when their final refuge on the extreme southern edge of the continent was overrun.9 Officially, the direct cause of their ultimate demise is a mystery, but I think we can guess who the culprit was.
There is certainly enough evidence to mark out a crime scene. One Neanderthal skeleton discovered in Iraq bears a peculiar puncture wound on one of its ribs – a mortal injury that is most consistent with a spear thrown by an anatomically modern Homo sapiens.10 In early 2009, the anthropologist Fernando Rozzi reported the discovery of a Neanderthal child’s jawbone, found together with anatomically modern human remains at the cave of Les Rois in southwestern France.11 The bone bore characteristic cut marks, similar to those found on butchered reindeer skulls, suggesting that the tongue had been cut out and eaten. Some loose teeth scattered around also had holes drilled in them, perhaps as parts of a morbid ceremonial necklace. Rozzi drew an unequivocal conclusion: ‘Neanderthals met a violent end at our hands, and in some cases we ate them,’ he said.12
There is even stronger evidence surrounding who killed most of the world’s largest animals, for their butchered bones are found stacked up everywhere humans invaded. As palaeontologist Richard Cowen writes in The History of Life, ‘From Russia to France, [archaeo-logical] sites contain the remains of thousands of horses and hundreds of woolly mammoths.’13 But the slaughter was far worse in the New World, where native species had no previous experience of this naked and harmless-looking but surprisingly rapacious two-legged predator. The North American death toll included six species of ground sloths, two species of mammoths, all mastodons, a giant bison, seven species of deer, moose and antelope, three species of tapirs, the North American lion, the dire wolf, the giant anteater, the giant turtle, the giant condor, all ten species of North American horses (then absent until reintroduced by invading sixteenth-century Europeans), two species of sabre-toothed cats, eight species of cattle and goats, the North American cheetah, four species of camels and two species of large bears.
But the biggest wipe-out of all took place in Australia, which saw a near-total extinction of large wild animals. The continent lost some extraordinary creatures: a gigantic horned turtle as big as a car, enormous flightless birds standing more than 2 metres tall and weighing half a tonne, a snake 6 metres long, and a giant predatory lizard that grew up to 7 metres in length and must have been the most fearsome reptilian predator since the dinosaurs. About twenty species of large marsupial disappeared, including a cow-sized wombat and a kangaroo 3 metres high. Quite how and when they died remains controversial: many archaeologists have tried to absolve Homo sapiens of the crime, pointing to the lack of kill sites and the low density of human population. But the extinction is roughly coincident with human arrival in the continent, and the pattern – affecting the largest species disproportionately – is exactly the same as everywhere else.
Further damning evidence comes from Tasmania, which retained its giant kangaroos (and various other megafauna) for four thousand more years, until falling sea levels allowed humans to finally invade – whereupon the island’s giant kangaroos (amongst six other large-bodied species) promptly died out.14 Any remaining doubters need only look to New Zealand. When Polynesian people first arrived by boat a mere 700 years ago, they found a unique island ecosystem where – thanks to millions of years of geographical isolation – birds rather than mammals or reptiles had evolved to become the dominant land animals. Giant flightless moas stalked the forests, whilst enormous eagles, the largest ever known, with wingspans of the order of 3 metres, soared above the mountains. Within as little as a century all – along with half of the islands’ other terrestrial vertebrates – were dead.15