Seahrse males carry pregnancies as known already and the degree to which male seahorses nourish and protect their embryos in their brood pouch during the 24-day gestation period is remarkable, said researchers.
“Surprisingly, seahorse dads do a lot of the same things human mums do,” said Camilla Whittington from the school of biological sciences.
Seahorse babies get a lot of nutrients from the egg yolk provided by their mothers, while they remain in their dad’s pouch and get additional nutrients and immunological protection, besides ensuring gas exchange and waste removal.
Dr Whittington and her team found male seahorses deliver nutrients to their developing embryos, particularly energy-rich lipids, and calcium that is required to build their tiny skeletons. These nutrients are said to have secreted in the brood pouch of dads and then absorbed by embryos.
They also found male seahorses’ gene expression during pregnancy was similar to that of humans. “The similarities between seahorse, mammal and lizard pregnancies revealed in the paper warrant further investigation,” Dr Whittington said. The findings have been published in the journal Molecular Biology and Evolution.
Apart from seahorses, their cousin species pipefishes too follow similar birth procedure. The male pipefishes become pregnant and give birth, but difer in terms of post-natal care.
Past findings from Texas A&M University showed that the male pipefish can be a nurturing father as it tends its young before giving birth, but later it may not choose to make the effort, according to a study by Kim Paczolt and Adam Jones, researchers in the Department of Biology, Texas A&M University.
The Texas A&M researchers studied consecutive broods in male Gulf pipefish to understand why some offspring survive while others do not.
Their results reveal that the males who were especially fond of the females they had mated with were more likely to show a nurturing attitude toward their offspring. In almost every case, those that were not overly fond of the mother were less nurturing toward their young.
“The bottom line seems to be, if the male likes the mom, the kids are treated better,” Paczolt said. Like the seahorse, the male pipefish becomes pregnant and gives birth.
Pipefishes and seahorses are part of a family of marine life called syngnathid fishes that have a unique reproductive system in which the male carries developing embryos. The male – not the female – provides for the embryo during their development.
Paczolt says by studying male pregnancy in seahorses and pipefish, “The whole phenomenon of male pregnancy is full of conflict and far more complex than we had previously realized.”