In the animal kingdom, pregnancy is almost always the responsibility of the female species type. From mammals to reptiles to birds, it is the female who typically nurtures the developing young. However, the key word within this statement is “almost.” Nature is full of exceptions and one of the most unique outcomes happens beneath the ocean’s surface. In the water, exists a species that requires the males to carry and birth the offspring. With horse-shaped heads, spiny bodily plates and curved tails, this species is better known as the seahorse.

Seahorse reproduction begins with an elaborate mating dance that can last up to nine hours. During this courtship dance, the male and female will spin, swim side by side and even change colors. Once the pair has synchronized through this ritual, the female will transfer her eggs to the male. She does this through a special structure called the ovipositor. This is a tube-like feature that allows the female to give her eggs to the male. This entire transfer process occurs quickly and takes up to six seconds. For egg storage, the male has a specialized organ known as a brood pouch. This pouch is typically located on the abdomen of male seahorses and it is used to protect, grow and provide nutrients to growing offspring. Depending on the species, the pregnancy of a male seahorse can last anywhere from 10 to 25 days. During this time they could be fertilizing and holding up to 2,000 offspring at a time.

Korean seahorse (Hippocampus haema) releases young into the water off the coast of Japan. Tony Wu Nature Picture Library 

At the end of the pregnancy, the male seahorse will go into labor. Prior to doing so, the male will focus on finding a safe area to hide to ensure the safety of his offspring. When the time has come he will undergo cramp-like contractions, much like other forms of labor. He will propel his offspring out of his brood pouch through each contraction. Once the young seahorses enter the water, they will be fully independent and will no longer receive parental care. With the completion of this process, the male will begin the mating cycle once again. This mating ritual has made seahorses one of the ocean’s most fascinating creatures. Consistently reminding society that even the rules of nature can be rewritten.

Citations

Laird, Isabella . “Seahorses Are Pregnant Fathers.” Beatymuseum.ubc.ca, 11 Sept. 2017, beatymuseum.ubc.ca/2017/09/11/seahorses-are-pregnant-fathers/.

National Geographic. “Seahorse Fathers Take Reins in Childbirth.” Pages, 14 June 2002, www.nationalgeographic.com/pages/article/seahorse-fathers-take-reins-in-childbirth.

Ortiz , Cristina . “Seahorses Are Tiny, Ravenous Creatures: Lifeform of the Week.” Earthsky.org, 12 Apr. 2024, earthsky.org/earth/seahorses-lifeform-of-the-week/.

“Reproduction: Seahorses Are the Only Animal Known to Have Male Pregnancy. How Cool Is That?” Project Seahorse, 10 June 2021, projectseahorse.org/saving-seahorses/about-seahorses/reproduction/.