The north of Yakutia has long been known to be an immense storehouse of frozen disjointed bones of many hundreds of thousands of large Pleistocene mammals—mammoths, horses, woolly rhinoceroses, bison, musk-oxen— “horned cattle”, as the first Russian travellers called them. Such knowledge had a commercial value, of whichmore will be said below, for the quarrying of mammoth ivory has gone on for many centuries. In quality these tusks, which have lain in frozen ground for tens of millennia, are as good as those of modern African and Indian elephants and are sometimes two or three times larger. For naturalists, the greatest interest lies in the discovery of whole frozen bodies or of skulls and complete skeletons. Study of the position of these bodiesand their morphology and of the contents of their stomachs and intestines may answer the age-old question of why the mammoth (or woolly elephant), together with this rich assemblage of large herbivores, died out. Would even a partial restoration of such previously abundant life be possible there today?