-faced bear, sabre-toothed cat, ground sloth and giant armadillo extinct. Not to forget the American camel and the American lion. Although this theory first emerged a year ago and has been hotly debated ever since, the authors of the Science article present compelling evidence to support it in the form of nanodiamonds. These, which are so small they are barely visible even under the most advanced microscopes, have been found embedded in 13000-year-old sediment in North America and Europe. …