Male seahorses play as much a part in nurturing embryos during pregnancy as human moms or other female mammals, suggests a new study. Previously their role, other than as pouch provider, was largely a mystery.
“When it comes to breeding, seahorses have more in common with humans than previously thought,” said researchers from the University of Sydney. Seahorses are famed for being part of the only species in the animal kingdom where the male is responsible for pregnancy.
What has not been known until now is the degree to which male seahorses nourish and protect their embryos in their brood pouch during the 24-day gestation period. “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 via the egg yolk provided by their mothers. But the pouch of the fathers has also evolved to meet the complex challenges of providing additional nutrients and immunological protection, and ensuring gas exchange and waste removal.
Dr Whittington and colleagues found male seahorses are able to deliver nutrients to their developing embryos, particularly energy-rich lipids, and calcium to allow them to build their tiny skeletons. It is likely these nutrients are secreted in the brood pouch 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 added. The paper was published in the journal Molecular Biology and Evolution.
