Travelers�even ones with naturalistic leanings�don�t ordinarily go to islands to watch land mammals, unless they happen to be interested in bats. This is partly because most people don�t associate mammals with island fauna. Birds, of course; reptiles, like lizards and snakes, certainly. And insects and spiders and other invertebrates by the legion. But not mammals, not usually. One might conclude from this that most islands never had any land mammals on them, which would be true in a strictly actuarial sense. But it would overlook the point that, in fact, many islands supported unique mammalian faunas until comparatively recently�indeed, until the appearance of humans. Then, in short order, the faunas collapsed, sometimes within scant decades after the first human footfall. In some cases the collapse affected mammals of large body size, while smaller species managed to survive. This is true, for example, of Madagascar, where only 1000 years ago there were gorilla-sized lemurs and short-legged hippos. These are all gone; today, the largest lemur, the teddy-like indri, weighs in at about 20 pounds. On other islands, the losses were utterly catastrophic: all land mammals, whether large or small, disappeared. This is what happened, for example, on some of the Galapagos islands, and on many of the islands of the central Mediterranean.