Home >> Science & Nature >> Nature

Why Do Male Seahorses Give Birth?

The seahorse is the common name for several species of small fish with elongated heads that resemble that of a horse. Unlike most other species, baby seahorses are incubated by their father rather than their mother.

Courtship Ritual
- Seahorse couples typically court for several days. Courtship often includes swimming side by side, holding onto the same stalk of grass and changing colors. During the ritual, the male opens the egg pouch on his chest, showing that it is empty.
Mating
- During mating, the male and female face each other as the female forces eggs into the male's pouch. After receiving the eggs, the male seahorse releases sperm into the water and then brings it into his egg pouch, fertilizing the eggs. The eggs incubate in the male's pouch for about 21 days.
Pregnancy
- The female seahorse keeps the male company for about six minutes every morning of his "pregnancy." They spend this time swimming side-by-side and holding tails. After 21 days, the male gives birth, expelling tiny seahorses from his pouch.
Considerations
- In 2007, Katrien van Look and other researchers at London's Institute of Zoology discovered that during mating, both the sperm and the eggs come into direct contact with seawater, making them vulnerable to pollutants, such as mercury. As of 2007, nine of the 33 species are considered vulnerable and one is listed as endangered.

Nature