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Pregnant Males

September 9, 2015

In seahorses, the males get pregnant and nurture the embryos.




A newborn Australian pot-bellied seahorse emerges from its father’s pouch. (Rudie Kuiter/Aquatic Photographics)

Male pregnancies. I’m Bob Hirshon and this is Science Update.

In a role reversal, male seahorses carry the babies, but they do much more than that. University of Sydney evolutionary biologist Camilla Whittington reveals in the journal Molecular Biology and Evolution that male seahorses have as large a role in nurturing embryos as human moms do.

CAMILLA WHITTINGTON (University of Sydney):

The female seahorse, she just gives him her eggs that are unfertilized and she pops them into his pouch. And as she does that he fertilizes those eggs, and he’s the one who does everything after that.


The team looked at how gene expression changed in the males during pregnancy.

Genes for providing nutrients, regulating oxygen, removing waste, and protecting from infection were all turned on in pregnant male seahorses, similar to gene changes in pregnant women. The research reveals how pregnancy evolved similarly in very different species — and even genders. I’m Bob Hirshon, for AAAS, the science society.