| Abstract: |
This study reevaluates the long-standing observation that human morphology varies with climate. Data on body mass, the body mass index [BMI
mass (kg)/stature (m)2], the surface area/body mass ratio, and relative sitting height (RSH
sitting height/stature) were obtained for 223 male samples and 195 female samples derived from studies published since D.F. Roberts' landmark paper Body weight, race, and climate in 1953 (Am. J. Phys. Anthropol. 11:533-558). Current analyses indicate that body mass varies inversely with mean annual temperature in males (r = -0.27, P < 0.001) and females (r = -0.28, P < 0.001), as does the BMI (males: r = -0.22, P = 0.001
females: r = -0.30, P < 0.001). The surface area/body mass ratio is positively correlated with temperature in both sexes (males: r = 0.29, P < 0.001
females: r = 0.34, P < 0.001), whereas the relationship between RSH and temperature is negative (males: r = -0.37, P < 0.001
females: r = -0.46, P < 0.001). These results are consistent with previous work showing that humans follow the ecological rules of Bergmann and Allen. However, the slope of the best-fit regressions between measures of body mass (i.e., mass, BMI, and surface area/mass) and temperature are more modest than those presented by Roberts. These differences appear to be attributable to secular trends in mass, particularly among tropical populations. Body mass and the BMI have increased over the last 40 years, whereas the surface area/body mass ratio has decreased. These findings indicate that, although climatic factors continue to be significant correlates of world-wide variation in human body size and morphology, differential changes in nutrition among tropical, developing world populations have moderated their influence.
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