The seahorse is a strange fish. Many of the traits it possesses have evolved in a direction unlike any other family of animals underwater—its bent S-shape; its head at a 90-degree angle to its body; its prehensile tail; and, most curiously, the male's brood pouch. A lab at Texas A&M University led by Adam Jones is currently studying these structures in the hope of understanding how it was that male pregnancy evolved in seahorses and how it affects the traditional sex roles in the fish.

Advertising agencies live by the aphorism that sex sells because it's one of the most basic, driving forces in our lives. Getting it, however, is a different matter altogether. In the animal kingdom, males and females of many species are known to trade resources for sex. Humans are no different. In the most basic terms, men can be said to offer protection to females, while females offer the promise of offspring to the males (we're talking caveman mentality here; let's leave the modern societal norms aside for a moment).

Although many jilted brainiacs might beg to differ, there’s no concrete evidence that women are more attracted to dumb men. Yet the same might not be true for some of our mammalian cousins. Consider, for example, the bat. After gathering available brain and testis size data for 334 species of bats, evolutionary biologist Scott Pitnick of Syracuse University found that males with the biggest cranial capacity were likely to have the smallest testicles, and vice versa.