Was the Mega Fauna (TM) in North America made extinct by a few hundred cave men scurrying around with pointy..?

...sticks? The Al Gore says it is true, so it must be. Also, this is currently the common belief among scientists and we all know that scientists have all the answers. Obviously a cave man with a pointy stick can run from California to Maine and kill a million+ mammoths, wooly rinocerous, and saber tooth tigers, and other species if he runs really fast and his stick is really pointy. Oh yeah, and Global Warming (TM) / Climate Change (TM) is true, too, 'cause most scientists believes it.