The male seahorse has a pouch on its stomach in which to carry babies—as many as 2,000 at a time. A pregnancy lasts from 10 to 25 days, depending on the species.

The reproductive process begins when a male and a female seahorse do daily pre-dawn dances, intertwining their tails and swimming together. Eventually they engage in a true courtship dance, which can last as long as eight hours. It ends with the female depositing her eggs in the male's pouch.

"Their mating ritual is quite beautiful," said Sarah Foster, a research biologist at McGill University in Montreal who is involved in Project Seahorse.

Scientists think the courtship behavior is designed to synchronize the movements of the two animals so that the male can receive the eggs when the female is ready to deposit them. The eggs are then fertilized in the dad's pouch.