An Evolutionary Choice: Brains or Balls

CNN.com has a great story on the evolutionary trade-off between smarts and sexual endowment.

A research team led by Syracuse University biologist Scott Pitnick found that in bat species where the females are promiscuous, the males boasting the largest testicles also had the smallest brains. Conversely, where the females were faithful, the males had smaller testes and larger brains.

The study offers evidence that males -- at least in some species -- make an evolutionary trade-off between intelligence and sexual prowess, said David Hoskens, a biologist at the Center for Ecology and Conservation at the University of Exeter in England and a leading authority on bats' mating behavior.

"Bats invest an enormous amount in testis, and the investment has to come from somewhere. There are no free lunches," said Hoskens, who did not participate in the study.

Read the entire story (CNN.com)

What I found most interesting was the influence of mating behavior on this trade-off, as described in the first paragraph. That suggests that monogomy aids cerebral development, something I hadn't heard anywhere before. But it makes sense.

What would be fascinating, obviously, is to determine if a similar phenomenon is observable in humans. Since most societies have covered their nakedness for thousands of years now, it would likely be hard to detect in all but the most primitive cultures.