Also people that evolve where there’s a winter have to plan, learn how to eat in winter. Those where there is no winter are weeded out by the climate.
Which is why the Neanderthals probably had higher IQs than Africans. They were one of the smartest apex predators to ever walk the face of Earth. But the modern myth that the Neanderthals went extinct because of climate change is laughable. They didn't just slip on a little bit of ice and fall off the face of Earth. They were pushed.