pipefish

At almost every aquarium I have ever visited with a seahorse exhibit, the plaque in front of the tank says the same thing: in seahorses and their relatives, males, not females, carry the babies. It is always interesting to watch the reactions of visitors to this curious fact. Adult men, for instance, sometimes seem unsettled by the thought of male pregnancy, but the reproductive reversal among the fish is often seen as kinda cute ("How sweet. A fishy dad taking care of his kids!"). As shown by a study by Kimberly Paczolt and Adam Jones published this week in Nature, however, there can be a…
For the pipefish (and their relatives, seahorses and sea dragons), it's the males who get pregnant.  After a male fertilises the female's eggs, he takes them up into a special brood pouch and shelters them until the babies hatch from his pot-bellied stomach several weeks later. He may seem like a shoe-in for the Dad-of-the-year award but this fatherly commitment has a sinister side to it. Not all of the babies he cares for make it out of his stomach alive. Gry Sagebakken from the University of Gothenburg has proved that pregnant male pipefishes absorb some of the eggs and embryos within…