As the Ice Age came to an end, North America lost a stunning variety of animals. Mammoths, mastodons, ground-dwelling sloths the size of elephants, beavers the size of bears, pronghorn antelope the size of poodles, llamas, and carnivores to chase them—sabertooth cats, dire wolves, American lions and cheetahs; these and many more were gone by 10,000 years ago. Giant Sloths and Sabertooth Cats surveys all these animals, with a particular focus on the Great Basin. The book also explores the major attempts to explain the extinctions. Because some believe that they were due to the activities of human hunters, the author also reviews the archaeological evidence left by the earliest known human occupants of the Great Basin, showing that people were here at the same time and in the same places as many of the extinct animals. Were these animals abundant in the Great Basin? A detailed analysis of the distinctive assemblages of plants that now live in this region leads to a surprising, and perhaps controversial, conclusion about those abundances.