Giant, human-sized beavers once roamed the wetlands and lakes of North America, coexisting with other ... However, roughly 10,000 years ago, they disappeared suddenly, leaving scientists perplexed ...

Graham Duggan Most archeologists agree that human beings reached North America 14,000 ... ancient predators about 10,000 to 20,000 years ago. But other, more plucky animals managed to hold on ...