Freak Felids - A Discussion of History's Largest Felines

[tigerluver]

Maybe a difference in the carnivora guild between the Americas kept S. fatalis smaller from the start? Or perhaps some type of social structure?

Panthera atrox probably arrived onto the Americas as massive as it was from the start because it was closely related to or simply an offshoot of P. fossilis. Considering the disappearance date of P. fossilis and relationship to P. atrox, P. atrox probably arrived onto America much earlier than fossil record shows. Thus, the S. fatalis and P. atrox interactions and thus evolutionary forces they had on each other probably started earlier too. 

Considering how the fossils recorded are rather recent, perhaps P. atrox being giant it was from its appearance inhibited S. fatalis slow progression to a larger size like its cousin in the south and thus by the end of its time, S. fatalis found it better to stop increasing in size and let P. atrox have the superpredator niche. Reply