The nostalgic outlook shared until recently by most of my environmentalist colleagues and myself is part of a human tendency to view the past as a Golden Age in many other respects. A famous exponent of this outlook was the eighteenth-century French philosopher Jean-Jacques Rousseau, whose Discourse on the Origin of Inequality traced our degeneration from the Golden Age to the human misery that Rousseau saw around him. When eighteenth-century European explorers encountered pre-industrial peoples like Polynesians and American Indians, those peoples became idealized in European salons as 'noble savages' living in a continued Golden Age, untouched by-such curses of civilization as religious intolerance, political tyranny, and social inequality. Even now, the days of classical Greece and Rome are widely considered to be the Golden Age of western civilization. Ironically, the Greeks and Romans also saw themselves as degenerates from a past Golden Age. I can still recite half-consciously those lines of the Roman poet Ovid that I memorized in tenth-grade Latin, 'Aurea prima sata est aetas, quae viydice nullo. . ('First came the Golden Age, when men were honest and righteous of their own free will. . ) Ovid went on to contrast those virtues with the rampant treachery and warfare of his own times. I have no doubt that any humans still alive in the radioactive soup of the Twenty-second Century will write equally nostalgically about our own era, which will then seem untroubled by comparison. Given this widespread belief in a Golden Age, some recent discoveries by archaeologists and paleontologists have come as a shock. It is now clear that pre-industrial societies have been exterminating species, destroying habitats, and undermining their own existence for thousands of years. Some of the best documented examples involve Polynesians and American Indians, the very peoples most often cited as exemplars of environmentalism. Needless to say, this revisionist view is hotly contested, not only in the halls of academia but also among lay people in Hawaii, New Zealand, and other areas with large Polynesian or Indian minorities. Are the new 'discoveries' just one more piece of racist pseudo-science by which white settlers seek to justify dispossessing indigenous peoples? How could the discoveries be reconciled with all the evidence for conservationist practices by modern pre-industrial peoples? If the discoveries were true, could we use them as case histories to help us predict the fate that our own environmental policies may bring upon us? Could the recent findings explain some otherwise mysterious collapses of ancient civilizations, like those of Easter Island or the Maya Indians?
Before we can answer these controversial questions, we need to understand the new evidence belying the assumed past Golden Age of environmentalism. Let's first consider evidence for past waves of exterminations, then evidence for past destruction of habitats. When British colonists began to settle New Zealand in the 1800s, they found no native land mammals except bats. That was not surprising, for New Zealand is a remote island lying much too far from the continents for flightless mammals to reach. However, the colonists' ploughs uncovered instead the bones and eggshells of large birds that were then already extinct but that the Maori (the earlier Polynesian settlers of New Zealand) remembered by the name moa. From complete skeletons, some of them evidently recent and still retaining skin and feathers, we have a good idea how moas must have looked alive: they were ostrich-like birds comprising a dozen species, and ranging from little ones 'only' 3 feet high and forty pounds in weight up to giants of 500 pounds and 10 feet tall. Their food habits can be inferred from preserved gizzards containing twigs and leaves of dozens of plant species, showing them to have been herbivores. They thus used to be New Zealand's equivalents of big mammalian herbivores like deer and antelope. While the moas are New Zealand's most famous extinct birds, many others have been described from fossil bones, totalling at least twenty-eight species that disappeared before Europeans arrived. Quite a few besides the moas were big and flightless, including a big duck, a giant coot, and an enormous goose. These flightless birds were descended from normal birds that had flown to New Zealand and that had then evolved to use their expensive wing muscles in a land free of mammalian predators. Others of the vanished birds, such as a pelican, a swan, a giant raven, and colossal eagle, were perfectly capable of flight.
Weighing up to thirty pounds, the eagle was by far the biggest and most powerful bird of prey in the world when it was alive. It dwarfed even the largest hawk now in existence, tropical America's harpy eagle. The New Zealand eagle would have been the sole predator capable of attacking adult moas. Although some moas were nearly twenty times heavier than the eagle, it still could have killed them by taking advantage of the moas' erect two-legged posture, crippling them with an attack on the long legs, then killing them with an attack on the head and long neck, and finally remaining for many days to consume the carcass, just as lions take their time at consuming a giraffe. The eagle's habits may explain the many headless moa skeletons that have been found. Up to this point I have discussed New Zealand's big extinct animals. But fossil-hunters have also discovered the bones of small scampering animals of the size of mice and rats. Scampering or crawling on the ground were at least three species of flightless or weak-flying songbirds, several frogs, giant snails, many giant cricket-like insects up to double the weight of a mouse, and strange mouse-like bats that rolled up their wings and ran. Some of these little animals were completely extinct by the time that Europeans arrived. Others still survived on small offshore islands near New Zealand, but their fossil bones show that they were formerly abundant on the New Zealand mainland. Collectively, all these now-extinct species that had evolved in isolation on New Zealand would have provided New Zealand with the ecological equivalents of the continents' flightless mammals that had never arrived: moas instead of deer, flightless geese and coot instead of rabbits, big crickets and little songbirds and bats instead of mice, and colossal eagles instead of leopards. Fossils and biochemical evidence indicate that the moas' ancestors had reached New Zealand millions of years ago. When and why, after surviving for so long, did the moas finally become extinct? What disaster could have struck so many species as different as crickets, eagles, ducks, and moas? Specifically, were all these strange creatures still alive when the ancestors of the Maoris arrived around 1000 AD?
At the time that I first visited New Zealand in 1966, the received wisdom was that moas had died out because of a change in climate, and that any moa species surviving to greet the Maoris were on their figurative last legs. New Zealanders took it as dogma that Maoris were conservationists and did not exterminate the moas. There is still no doubt that Maoris, like other Polynesians, used stone tools, lived mainly by farming and fishing, and lacked the destructive power of modern industrial societies. At most, it was assumed, Maoris might have given the coup de grace to populations already on the verge of extinction. However, three sets of discoveries have demolished this conviction. Firstly, much of New Zealand was covered with glaciers or cold tundra during the last Ice Age ending about 10,000 years ago. Since then, the New Zealand climate has become much more favourable, with warmer temperatures and the spread of magnificent forests. The last moas died with their gizzards full of food, and enjoying the best climate that they had seen for tens of thousands of years.