Male seahorses are like human females when it comes to nurturing their young

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A new study has shed light on the nurturing role of male seahorses during the 24-day gestation period – a finding that reveals a previously unknown side of the seahorse behaviour.

Researchers at University of Sydney have likened the behaviour of male seahorses to that of human females. Keeping in line with the reputation of being the only males in the animal kingdom that are responsible for pregnancy, male seahorses nourish and protect their embryos in their brood pouch.

According to Dr Camilla Whittington from the University’s School of Biological Sciences, seahorse dads do a lot of the same things human mums do. Dr Whittington explains that while the seahorse babies get a lot of nutrients from the egg yolk provided by their mothers, the father’s pouch has evolved as well to enable the male to nurture their young ones by providing additional nutrients and immunological protection, as well as ensuring gas exchange and waste removal.

The researchers found that male seahorses deliver energy-rich lipids, and calcium to the developing embryos enabling them to build their tiny skeletons. Researchers believe that the nutrient delivery mechanism is likely to involve secretion in the brood pouch and then absorption by embryos.

They also found male seahorses’ gene expression during pregnancy was similar to that of humans. Their research involved taking samples from brood pouches and assessing how gene expression changed during the course of the pregnancy. It is the first RNA sequencing study – monitoring how much genes switch on and off – across the full course of pregnancy in any animal.

“Regardless of your species, pregnancy presents a number of complex challenges, like ensuring you can provide oxygen and nutrients to your embryos. We have evolved independently to meet these challenges, but our research suggests that even distantly related animals use similar genes to manage pregnancy and produce healthy offspring.”

The similarities between seahorse, mammal and lizard pregnancies revealed in the paper warrant further investigation, Dr Whittington said. This will indicate whether the evolution of animal pregnancy across all species is more similar than previously thought.