The idle ramblings of a Jack of some trades, Master of none

Dec 3, 2007

Harems revisited

If, in a species, the male is way, way heavier and bigger than the female, you may be sure that the social structure is like an Ottoman and his harem. This is called sexual dimorphism, and has been observed in several species, notably gorillas. Now, anthropologists have found evidence that one of the parallel branches of human evolution, the African Paranthropus robustus, displayed a similar dimorphism and all its concomitant consequences.

About two million years ago, the dominant males of this species would hoard all available females and push the wimpy males out of the commune. These wimpy males - mature, but not big or strong enough to attract any female attention - would band together for protection, and many would fall prey to predators (e.g. leopards): fossil records show that males were killed more often than female. The females appeared to live in secure stable groups that would allow a key male to take over the harem. A high-risk, high-reward strategy, then! If you survived and grew strong in the wild, you might live to challenge a dominant male; defeat him and the harem was yours. You might then live the good life until another twerp destroyed you in due time. In the meanwhile, your own genes would have propagaged nicely and posterity would remember you as a kindly old soul.

Yup, the good life.

Meanwhile, here is a somewhat ungrammatical argument against some of the conclusions.

The original paper is here.


rajesh said...

do you think that the same sexual dimorphism as seen in gorillas is the reason that over the years created human homosexuals? imagine all the weak men pushed out of the race for women while the rich or the powerfull hoarded all the women in their harems... and they needed to satisfy their urges.... and they invented KY Jelly!!!

Fëanor said...

rajesh: i'm not sure if you are pulling my leg! there are a few reasons why i think your analogy is not accurate. one, there is no sexual dimorphism in humans, and in those animals where it manifests (e.g. lions), the subordinate males do not form homosexual bondings; in fact, they roam around in search of females that they can surreptitiously impregnate. two, in animals (e.g. bonobos) where there is evidence of homosexual behaviour, it is not exclusively so! three, harems are not a biological construct for humans and only seem to have arisen at higher social strata, so the weak men you speak of would have had access to the myriads of women who were not part of harems. and lastly, a superior male mounts subordinate males in some species to assert his dominance - i don't think there's any penetration! and this behaviour doesn't exist in humans. so the inventor of ky jelly must have been thinking about something else! ;-)

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