If male seahorse bears babies, what make them male?
As mentioned, male seahorses still produce sperm, and the female still produces the eggs. The males are just holding the eggs until they hatch. If you look at related species, such as a sea dragon, it makes a little more sense. A sea dragon male has a patch of skin on its tail that the female deposits the eggs, but there is no enclosure. Seahorses just took it to the next step by completely enclosing the pouch. In many non-mammal species, males take on a much more prevalent role in raising the young. This is partially because the female is not required after birth. If a male raises/protects its offspring, then it is ensuring that its genetic code can be passed on.
