seahorses

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.