In seahorses, the male gives birth.

In seahorses, the male gives birth.  This is partly because we consider the sex of an animal by the size of its gametes (sex cells)-- so the ones with the larger gametes are considered females, and the smaller are males.  In seahorses, the males carry the baby and give birth.

I also learned a new term-- "seahorse dads"-- to describe trans men who give birth

https://youtu.be/MsHCqrrU-Gk

https://theconversation.com/the-secret-sex-life-and-pregnancy-of-a-seahorse-dad-46599#:~:text=Even%20though%20fish%20don't,(sex%20cells)%20they%20produce.