Because of all the short vikings and tall Vietnamese? "Allen’s Law, which dictates that body shapes in endotherms (warm-blooded animals) adapt to climatic cond

Because of all the short vikings and tall Vietnamese? "Allen’s Law, which dictates that body shapes in endotherms (warm-blooded animals) adapt to climatic conditions—short and stocky helps retain heat in cold climates, while tall and lanky helps dissipate heat in warmer ones. "