Probably the only primates where a significant portion spent tens of thousands of years isolated up in the Arctic during prehistoric times. Where the sun doesn

Probably the only primates where a significant portion spent tens of thousands of years isolated up in the Arctic during prehistoric times. Where the sun doesn't go down every single day anyhow, and you may need to trudge across the tundra routinely for more than 24 hours at a stretch to get almost anywhere, without ever worrying about it at all. Then they later came down and intermixed with (not) everyone else, so you never know who is going to be less tired than "normal" when they work a 36-hour day.