Why do seahorse dads carry the babies?
For grown-ups: the science
Seahorse dads have a belly pouch where eggs grow into babies with oxygen and nutrients until they hatch.
In seahorses and their close relatives, the female transfers eggs into the male's brood pouch. The male fertilizes them and provides a protected, regulated environment, including gas exchange and nutrient transfer, until the young are released. Scientists do not know for sure exactly which evolutionary advantage first favored male brooding, and it should not be presented as settled fact that this evolved specifically so females could make eggs faster.
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Transcript
A seahorse dad swims with a round pouch on his belly. Why does he carry the babies?
A seahorse mom places her eggs inside the dad's special belly pouch. Then the dad fertilizes the eggs, which helps them begin growing.
The pouch holds the growing babies safely while the dad swims. It gives them oxygen and nutrients, like food for growing.
When the babies are ready, tiny seahorses come out of the pouch. Nobody knows for sure why this dad job began long ago.
So seahorse dads carry babies in a special pouch where they can grow. What an unusual family job!