some scientists say that the human body has adapted biologically over thousands of years Bergman a German biologist living in the 19th century studied how animals adapt to different climates and his findings led him to create the Bergman rule this rule states that individuals of a particular species living in a cold environment will have a greater body mass and relatively smaller body surface area than those living in a hot environment The polar bear is a very clear example of this biological modification the polar bear has a larger and more compact body and surface area smaller than that of bears who live in warmer climates the consequence of this adaptation is much less heat loss to the surface of the body that originally the Birdman role was applied to animals on me though subsequently it has been applied to the human species two of course application of the rule is limited but to some extent it does describe differences between human populations