yeah, i think we're all talking around some version of bergman's rule and allan's rule. this is me explaining them in a lecture a while back:
https://www.youtube.com/watch?v=2n-Nkup_uQc
in short, you combine the idea that hot weather animals are usually less massive than their cold-weather counterparts with the idea that there are some interesting geometrical rules about the relationship between volume (mass) and surface area.
you're onto something with the sphere idea; darwin wants people in cold climates to be more spherical (short appendages, more central body mass) and hot climates to be cylindrical (long and lean). the cylinder gives you more surface area for the same mass compared to the sphere.
so all else equal a longer, leaner person is able to radiate heat better than a shorter, rounder one.
of course none of this addresses differences in fitness, clothing, pacing, nutrition, and etc etc.
____________________________________
https://lshtm.academia.edu/MikeCallaghan
http://howtobeswiss.blogspot.ch/
https://www.youtube.com/watch?v=2n-Nkup_uQc
in short, you combine the idea that hot weather animals are usually less massive than their cold-weather counterparts with the idea that there are some interesting geometrical rules about the relationship between volume (mass) and surface area.
you're onto something with the sphere idea; darwin wants people in cold climates to be more spherical (short appendages, more central body mass) and hot climates to be cylindrical (long and lean). the cylinder gives you more surface area for the same mass compared to the sphere.
so all else equal a longer, leaner person is able to radiate heat better than a shorter, rounder one.
of course none of this addresses differences in fitness, clothing, pacing, nutrition, and etc etc.
____________________________________
https://lshtm.academia.edu/MikeCallaghan
http://howtobeswiss.blogspot.ch/