This only really applies to some animals which developed in moderate climate. Most primates including us humans are tropical and subtropical creatures, which d

This only really applies to some animals which developed in moderate climate. Most primates including us humans are tropical and subtropical creatures, which didn't face classical winters until relatively recently. The Neanderthals did, for a considerable amount of time, and their physiology might have been different, but the Neanderthals were also developed enough to protect themselves using clothing and shelters, and possibly store food, so physiological adjustments might not have been necessary. Modern humans are basically Africans adapted to ~ Kenyan climate, though. (Yeah I know about the Neanderthal and Denisovan admixture.)