Sexual ornaments grow out of all proportion:
The male obsession with size appears to be universal, according to a new survey of animal species where males use ornamental body parts to attract females. The study showed that sexual ornaments – such as antlers or a peacock’s feathery display – become disproportionately large as body size increases.
Most body parts grow proportionally with the rest of the body as individuals of a species become larger, although scientists have long known that visual cues of reproductive prowess are a special case.
Now, in the largest survey to date, James Brown at the University of New Mexico, Albuquerque, US, and his colleagues have examined the proportions of 284 ornament-bearing species to see whether the tendency was truly universal. They found that in virtually every case, ornament size grew by roughly the square of the overall growth rate.
By the square of the growth rate. Sheesh.
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