Several theories have been advanced to explain the great loss of large animals in North America, mostly mammals, at the end of the Pleistocene Epoch roughly 10,000 years ago.  The three dominant hypotheses are: 1) human overhunting, 2) climate and environmental change, and 3) disease.  Each hypothesis has its merits, yet some facets of each approach are difficult to test.  Overhunting proponents have long made the basic argument that the extinct species shared the characteristic of being easy prey, and that the surviving species were, in contrast, difficult for humans to hunt.  Unfortunately, the extinct species offer no real possibility to test this idea.  However, our living megafauna do.  The modern line-up of large mammals in North America spans a wide range of niche specializations and anti-predation behaviors.  This observation is supported by the diverse habitat affinities of the surviving species, apparently well-tuned to the modern climate, and in the widely varied hunting statistics for modern big game animals.  Instead of simply being difficult to hunt, our surviving megafauna appear to be a diverse group well adapted to the post-glacial climate following the Pleistocene..