Various species of rodents, bats, insectivores, and relatives of mongooses also occur, yet the largest still only weighs about twenty-five pounds.

However, littering Madagascar's beaches are proofs of vanished giant birds, in the form of countless eggshells of the size of a soccer ball. Eventually, bones turned up not only of the birds that laid those eggs, but also of a remarkable suite of vanished large mammals and reptiles. The egg-makers were half-a-dozen species of flightless birds up to 10 feet tall and weighing up to 1,000 pounds, like moas and ostriches but more massively built and hence now termed elephant birds. The reptiles were two species of giant land tortoises with shells about a yard long, and formerly very common, as indicated by the abundance of their bones. More diverse than either of these large birds or reptiles were a dozen species of lemurs up to the size of a gorilla, and all larger than or at least as large as the largest surviving lemur species. To judge from the small size of the eye orbits in their skulls, all or most of the extinct lemurs were probably diurnal rather than nocturnal. Some of them evidently lived on the ground like baboons, while others climbed in trees like orangutans and koala bears.

As if all this were not enough, Madagascar also yielded the bones of an extinct 'pygmy' hippopotamus ('only' the size of a cow), an aardvark, and a big mongoose-related carnivore built like a short-legged puma. Taken together, these extinct large animals formerly gave Madagascar the functional equivalents of the surviving large beasts for which tourists still flock to African game parks—just as did New Zealand's moas and other strange birds. The tortoises, elephant birds, and pygmy hippo would have been the herbivores replacing antelope and zebras; the lemurs would have replaced the baboons and great apes; and the mongoose-related carnivore made do for a leopard or scaled-down lion. What happened to all these big extinct mammals, reptiles, and birds? We can be confident that at least some of them were alive to delight the eyes of the first arriving Malagasy, who used elephant bird eggshells as water containers and discarded butchered bones of the pygmy hippo and some of the other species in their rubbish heaps. In addition, the bones of all the other extinct species are known from fossil sites only a few thousand years old. Since they must have evolved and survived for millions of years until then, it is unlikely that all those animals had the foresight to give up the ghost just in those last few moments before hungry humans showed up. In fact, a few may still have been holding out in remote parts of Madagascar when Europeans arrived, since the seventeenth-century French governor Flacourt was given descriptions of an animal suggestive of the gorilla-sized lemur. The elephant birds may have survived long enough to have become known to Arab traders in the Indian Ocean, and to have given rise to the account of the rok (a giant bird) in the tale of Sinbad the Sailor.

Certainly some and probably all of Madagascar's vanished giants were somehow exterminated by the activities of the early Malagasy. It is not hard to understand why the elephant birds became extinct, since their eggshells made such convenient two-gallon jerrycans. While the Malagasy were herders and fisherman rather than big-game hunters, the other big animals would have been easy prey, since they had never seen humans before. Probably, like New Zealand's moas, they were as tame as Antarctic penguins and other creatures that evolved in the absence of humans. A hungry Malagasy could have walked up to one of those tame beasts, clubbed it, and enjoyed a quick barbecue. That is presumably why the easy-to-see, easy-to-catch lemurs big enough to be worth the effort of butchering them—the large, diurnal, terrestrial species—all became extinct, while the small, nocturnal, tree-living ones all survived.

However, unintended by-products of Malagasy activities probably killed more big animals than did hunting. Fires lit to clear forest for pasture and to stimulate growth of new grass each year would have destroyed habitats on which the beasts depended. Grazing cattle and goats also transformed habitats, as well as competing directly with grazing tortoises and elephant birds for food. Introduced dogs and pigs have preyed on ground-dwelling animals, their young, and their _eggs. By the time that the Portuguese arrived, Madagascar's once-abundant elephant birds had all been reduced to eggshells covering the beaches, skeletons in the ground, and vague memories of roks. Madagascar and Polynesia merely provide well-documented examples of the extinction waves that probably unfolded on all large oceanic islands colonized by people before the European expansion of the last 500 years. Like New Zealand and Madagascar, all such islands where life had evolved in the absence of humans used to have unique species of big animals that modern zoologists never saw alive. Mediterranean islands like Crete and Cyprus had pygmy hippos and giant tortoises (just as did Madagascar), as well as dwarf elephants and dwarf deer. The West Indies lost monkeys, ground sloths, a bear-sized rodent, and owls of several sizes: normal, giant, colossal, and titanic. It seems likely that these big birds, mammals, and tortoises too somehow succumbed to the first Mediterranean peoples or American Indians to reach their islands. Nor were birds the only victims. Mammals, lizards, frogs, snails, and even large insects disappeared as well, comprising thousands of species when one adds up all oceanic islands. Olson describes these insular extinctions as 'one of the swiftest and most profound biological catastrophes in the history of the world'. However, we will not be sure that humans were responsible until the bones of the last animals and the remains of the first people have been dated more exactly for other islands, as has already been done for Polynesia and Madagascar.

In addition to these pre-industrial extermination waves on islands, other species may have fallen victim to extermination waves on continents, in the more distant past. About 11,000 years ago, around the probable time that the first ancestors of American Indians reached the New World, most large species of mammals became extinct throughout all of North and South America. The disappearances involved species as varied as lions, horses, giant armadillos, mammoths, and saber-toothed cats. A long-standing debate has raged over whether these big mammals were done in by Indian hunters, or whether they just happened to succumb to climate changes around the same time. I shall explain in the next chapter why I personally think that hunters did it. However, it is much harder to pinpoint dates and causes of events that happened around 11,000 years ago than it is for recent events, like the collision of the Maoris and the moa within the past thousand years. Similarly, within the past 50,000 years Australia lost most of its big mammal species and was colonized by the ancestors of today's Aboriginal Australians, but we are still uncertain whether the second event caused the first. Therefore, although it is now reasonably certain that the first pre-industrial peoples to reach islands wrought havoc among island species, the jury is still out on the question of whether this also happened on continents. From all this evidence that the Golden Age was tarnished by exterminations of species, let's now turn to evidence for destruction of habitats. Three dramatic examples involve famous archaeological puzzles: the giant stone statues of Easter Island, the abandoned pueblos of the American Southwest, and the ruins of Petra.

An aura of mystery has clung to Easter Island ever since it and its Polynesian inhabitants were 'discovered' by the Dutch explorer Jakob Roggeveen in 1722. Lying in the Pacific Ocean 2,300 miles west of Chile, Easter surpasses even Henderson as one of the world's most isolated scraps of land. Hundreds of statues, weighing up to eighty-five tons and up to 37 feet tall, were carved from volcanic quarries, somehow transported several miles, and raised to an upright position on platforms, by people without metal or wheels and with no power source other than human muscle. Even more statues remain unfinished in the quarries, or lie finished but abandoned between the quarries and platforms. The scene today is as if the carvers and movers had suddenly walked off the job, leaving an eerily silent landscape. When Roggeveen arrived, many statues were still standing, though new ones were no longer being carved. By 1840 all the erected statues had been deliberately toppled by the Easter Islanders themselves. How were such huge statues transported and erected, why were they eventually toppled, and why had carving ceased?