Male seahorses give birth by releasing their young offspring into the water once the eggs hatch. Fertilized eggs are stored in a brood pouch on the ventral side of the animal during a gestation period ranging from 14 days to four weeks.
During mating, the female deposits her eggs into the pouch, which are then fertilized internally by the male. The number of eggs ranges from 50 to 150 in smaller species to up to 1,500 among larger seahorses. Seahorses are unique in that they mate in pairs for life and are the only animal species on the planet in which the male carries the unborn young.