Why do male seahorses give birth??

                 Why do Male Seahorse Give Birth??

     Seahorse males do something highly unusual in the animal kingdom; they get pregnant and deliver their offspring. Scientists don't have a clear reason why seahorses evolved this way, but they theorize this is one of the ways seahorses try to help the species survive. Neither parent gets involved in the child-rearing, though. When the male delivers the babies, they are on their own.
                                           
                                                         

How It Works

Although the male carries the eggs, he doesn't make them. After a male and female seahorse spend time courting, the female deposits her eggs inside the male's pouch. He fertilizes the eggs inside the pouch. His pouch is a complex organ that regulates temperature, blood flow and water salinity for the eggs as they hatch so the babies are as prepared as possible for life in the ocean.

Making More Babies

One theory about why male seahorses carry the babies is that this gives the species the ability to create more babies quickly. The female deposits all her available eggs into his pouch when they mate, so she needs time to make more eggs. While he's carrying one set of eggs, she's creating more so they are ready when the first group is born. The male can deliver babies in the morning and get pregnant again the same day. The female expends her energy making more eggs rather than carrying fertilized ones.

Seahorse is the name given to 54 species of small marine fishes in the genus Hippocampus. "Hippocampus" comes from the Ancient Greek word hippos meaning "horse" and kampos meaning "sea monster". The word "seahorse" can also be written as two separate words (sea horse), or hyphenated (sea-horse). Having a head and neck suggestive of a horse, seahorses also feature segmented bony armour, an upright posture and a curled prehensile tail

The male seahorse is equipped with a pouch on the ventral, or front-facing, side of the tail. When mating, the female seahorse deposits up to 1,500 eggs in the male's pouch. The male carries the eggs for 9 to 45 days until the seahorses emerge fully developed, but very small. Once the young are released into the water, the male's role is done and he offers no further care and often mates again within hours or days during the breeding season.^[16]

Courtship

Before breeding, seahorses may court for several days. Scientists believe the courtship behavior synchronizes the animals' movements and reproductive states so the male can receive the eggs when the female is ready to deposit them. During this time, they may change color, swim side by side holding tails or grip the same strand of sea grass with their tails, and wheel around in unison in what is known as a "predawn dance". They eventually engage in a "true courtship dance" lasting about 8 hours, during which the male pumps water through the egg pouch on his trunk which expands and opens to display its emptiness. When the female’s eggs reach maturity, she and her mate let go of any anchors and drift upward snout-to-snout, out of the seagrass, often spiraling as they rise. They interact for about 6 minutes, reminiscent of courtship. The female then swims away until the next morning, and the male returns to sucking up food through his snout.^[17] The female inserts her ovipositor into the male’s brood pouch and deposits dozens to thousands of eggs. As the female releases her eggs, her body slims while his swells. Both animals then sink back into the seagrass and she swims away.^{[citation needed]}

Fertilization

During fertilization in Hippocampus kuda the brood pouch was found to be open only for six seconds while egg deposition occurred. During this time seawater entered the pouch where the spermatozoa and eggs meet in a seawater milieu. This hyperosmotic environment facilitates sperm activation and motility. The fertilization is therefore regarded as being physiologically ‘external’ within a physically ‘internal’ environment after the closure of the pouch.^[18] It is believed that this protected form of fertilization reduces sperm competition among males. Within the Syngnathidae (pipefishes and seahorses) protected fertilization has not been documented in the pipefishes but the lack of any distinct differences in the relation of testes size to body size suggests that pipefishes may also have evolved mechanisms for more efficient fertilization with reduced sperm competition.^[19]

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