Smilodon is the most famous of North America's long-lost sabercats. But the burly carnivore wasn't the only long-fanged carnivore prowling the continent during the last Ice Age. The remains of Homotherium serum - a cougar-sized cat with shorter, serrated canines - have been found at sites from Alaska to Texas, including a den near San Antonio that contains the bones of baby sabercats as well as the dismembered remnants of little mammoths that were dragged back to the cave. And the record of Homotherium goes beyond bones. In a Boreas paper published last year, paleontologist Chris Widga and colleagues ...