COURTSHIP: Seahorses court for several days at a time. The courting ritual involves dancing, changing colour and entwining tails. Sometimes, more than one male seahorse will compete to win the affections of a female, or vice versa. Males can inflate their pouch by pumping water through it to display its emptiness. This is to entice the female to deposit her eggs in it.
EGG TRANSFER: The female deposits her egg in the water in order to transfer to the males pouch. The male releases his sperm directly into seawater to fertilize the eggs. They are then embedded in the pouch wall and become surrounded by a spongy tissue. The number of eggs varies between species.
PREGNANCY: Although the male carries the baby, the initial conditions in the pouch are determined by the nutrients provided by the female, but when the eggs are in the pouch conditions are controlled by the male. He provides oxygen and nutrients through a network of capillaries. The embryos will remain in the pouch for two to six weeks, depending on species and temperature, as they develop into fully formed juveniles.
BIRTH: When the male seahorse is ready to give birth he has muscular contractions to expel the young, which are known as fry, from the pouch.
YOUNG: Newborns measure between two and twelve millimetres, depending on species. The number of young produced ranges between 100 and 200 for most species, but can be as low as 5 for the smaller species, or more than 1,500 for larger species. The fry will often grasp floating or still objects, and even each other, with their tails.
JUVENILES: Newly released young undergo only small changes after emerging from the father. During growth some body proportions may change but they don’t experience major body changes. Some newborns emerge with a small fin which is lost over time.
ADULT: Mature male seahorses have the ability to become pregnant any time during the breeding season, which varies with species. This is thought to be influenced by environmental conditions such as water temperature.