My assumption: like with any territorial animal, to avoid competing with other tribes over resources. And apart from the very very cold places like Greenland, most cold places actually are abundant in food when spring comes, which would be the time tribes would venture further north in cold climates.
Yep.
And it’s not like someone went from Africa to Greenland on a walkabout.
It took generations for that kind of migration, some people decided they went far enough and stopped. But at every stop, the ones who could handle colder would expand North/South where there’s less competition.
They were repeatedly being selected for the people who could handle a slightly colder environment, so by the time the population reached the polar regions, all that was left was people with traits to handle the cold. Any remotely beneficial recessive gene would quickly replace dominant alleles in the population.
People think of evolution as spontaneous mutations, but really it’s just the concentration of recessive genes that have been around basically forever
The current era of excess is unprecedented in the history of the world. For most of human history, starvation was a serious threat and hungry people would go anywhere where there was food that wasn’t already claimed by someone stronger than them.
(The people in very cold climates would fight to defend their resources too! Ultimately there was no unclaimed land that people could survive in, except shortly after major catastrophes.)
It’s a good point that competition can drive animals to areas they wouldn’t choose. But it’s also true that pioneering a new niche can lead to animals thriving rather than just surviving.
My understanding is that we are currently living in an interglacial period.
I believe the pattern on Earth recently has been you get these relatively mild climates that last around 10 thousand years, in between 100 thousand years of ice age.
So, maybe the climate was harsh pretty much everywhere that wasn’t the equator for most of time our species has existed.
Hunting seals and whales in some cases, as in Alaska.
Yep, following food.
Or, it wasn’t as harsh when they first appeared. I mean there was the Little Ice Age in Shakespeare’s time, where the Thames froze over. If you took that as a sign it was becoming permanently like that in London, what would you do? It’s not like you have somewhere else to go that you know it’s better (or hell, where anything is).
People in the 20th century easily forget how little knowledge the average person had even 100 years ago. Hell, even the information the wealthy had. Just a couple hundred years ago a globe of the earth was practically priceless. They were still a luxury in the early 20th century.
