Diverse bunch
Chances are you put your height and girth down to your genes. While height variations within a population are largely genetic, where you live in the world also affects the size and shape of your body. People living at low latitudes, such as the Nilotics in equatorial Africa, tend to have narrow bodies and few curves, while Eskimos living in Arctic regions have wider bodies and a bulkier physique. In fact, detailed studies by anthropologists have revealed that the width of the human body varies by about 25 per cent between different populations and increases as you go from low to high latitudes (see graph). In contrast, height does not follow any obvious geographic trend.
So why the link between build and geography? Anthropologists believe it is all down to climate and, in particular, the way our bodies lose heat. Humans rely largely on sweating to cool themselves down. In hot climates, having a large surface area relative to body mass means that you can lose more body heat through increased radiation, convection and evaporation. Likewise, people living in cold climates retain more heat if they have a smaller surface area to mass ratio. All else being equal, having a wider body leads to a lower ratio of surface area to mass, and explains the geographical trend.
“Laid end to end, your blood vessels would wrap 2.5 times round the Earth”
Sweating is not an effective way to cool down in extremely humid environments where there is little or no air movement. In hot, steamy rainforests the best way to prevent overheating is to limit the amount…
