Sunday, October 28, 2012

On Sexual Dimorphism in Humans

On common evolutionary argument about humans is that we have a tendency to polygamy. The degree of the tendency is debated, but factors like sexual dimorphism - that males are larger than females - is seen as supporting polygamy, since species with larger males typically are ones in which males compete for females, and that competition favors larger males.

For humans specifically though, there is at least one other explanation. Different gender roles are posited in our ancestors, where men hunt and women gather. This is an oversimplification of present-day hunter-gatherers, and we do not have conclusive evidence of our ancestor hunter-gatherers, but assuming this is the case, male size could be favored because of the different work they do: hunting large animals benefits from greater physical strength. A related argument could be made about tool-making: If men build shelter or craft weapons, physical strength is useful.

Which evolutionary theory, if any, is the right one? I don't think we have a good guess.

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