The Cave Lion (Panthera spelaea and Panthera fossilis)

[tigerluver]

Bergmann's rule is simply not that accurate as more data rolled in historically and the assumptions made by the rule are much too volatile and to a degree paradoxical. Cold regions are hostile to high biomass and diversity as compared to warmer regions usually, thus the assumptions of the Bergmann's rule are very difficult to meet. For instance, P. atrox and P. spelaea from Alaska were rather small compared to the counterparts in California and Germany, respectively. 

Copious fossil data shows that P. atrox was definitely larger than the late Pleistocene P. spelaea. This as of yet cannot be argued as there are relatively plenty of fossils for these species. P. fossilis, on the other hand, seems to have matched and surpassed P. atrox. Do note that P. fossilis is a very likely candidate to be the progenitor group of P. atrox.

Lastly, the idea of being further northern would be less accurate than saying the further one goes from the equator. Remember, temperature, the factor behind Bergmann's rule, drops as one moves toward both poles. Reply