They are not exposed to extremely low temperatures though, it can’t get much below zero in the sea for obvious reasons.
That probably explains the dearth of blubber suits among cold weather gear.
I suppose the real difference is insulating in air vs insulating in water. Neoprene wet suits would be the human equivalent of blubber.
Water is vastly more efficient at removing heat than air.
Cold water robs the body’s heat 32 times faster than cold air.
Sure, but that just proves the point that insulating the body in water is not the same as insulating it in air, and the best solutions may be different.
So, that’s an interesting question.
How cold does the air need to be before it kills you from hypothermia as quickly as nearly freezing seawater?
Back on topic, homeless people in very cold climates have to find some kind of shelter or heat in order to survive: