While seahorses certainly are a unique-looking fish, that’s hardly their most unusual trait. Seahorses and their relatives, pipefishes, are the only family of fish in which the males become pregnant and give birth.
The process begins with males seeking out the largest females, who provide the largest size and greatest number of eggs. The pair swim together, “hold tails” and “dance” for several mornings. Then, an 8-hour courtship dance leads to the actual mating.