Don't know if this should be here or ASB and counts as an evolution based topic but I'm putting it here as its grounded in reality (if this isn't the right place I ask it be moved to ASB.) I was reading Guns, Germs, and Steel and at one point in the book the author speculates on why the megafuana that lived in the Pleistocene (mammoths, Smilodons, giant Australian Komodo Dragons etc.) went extinct and concluded that it was probably caused by humans as in North America for example ice ages had began and ended many times and the megafuana survived all of them. The extinction of the megafuana coincided with the colonization of the land areas in which the megafuana lived by human hunter gatherers. His theory is that the megafuana survived in Africa because they had evolved alongside humans and thus had a greater fear and coping mechanisms against them which allowed them to survive. North American, European, South American, Oceanian, and other megafuana weren't adapted to dealing with humans. So, if this theory is true, how do you get the megafuana to survive into the modern era and have history play out as normal or at least in a recognizable fashion? To put it another way, is there a POD possible which allows humans and megafuana to coexist in the Americas and Oceana like they do in Africa? And if the megafuana survive and its impossible for it not to change history, how does it effect history?