What a funny name for such a small and harmless little creature. Hippo – horse and campus – sea monster. They are about 54 different species and the slowest swimmers in the ocean. The smallest one have a top speed of 1,5 meters per hour. Can you imagine? At that speed you have to plan things. Its habitat usually extends to around 3 square feet. That means that the total habitat where it spends its life is within an hour swimming radius.
But when I start reading about these small and fragile creatures it is such a wonderful story. A lot of extensive research is available.
In the hippocampus world it is the male giving birth to the young- the roles are reversed.
The male seahorse is equipped with a pouch on the ventral. When mating, the female seahorse deposits up to 1,500 eggs in the male’s pouch. The male supplies the eggs with prolactin, the same hormone responsible for milk production in pregnant mammals. The male carries the eggs for 9 to 45 days until the seahorses emerge fully developed. When the fry are ready to be born, the male expels them with muscular contractions. You may find clips of this on YouTube. You can clearly see how the male goes into labor. Breathing increase, he gets contractions and then he releases all the young. The smaller species can have as little as 5-10 babies and the larger up to a thousand.
This is one of the few species on earth where the roles are opposite and the males perform the majority of the parental care. Why does this happen? Does this make the offspring better prepared for survival? Is the pouch a safer place during hatching? Who knows? You may find some answers reading about the Bateman’s Principle from 1948 or the studies from Robert Trivers about variables in reproduction success. Batemans studies were made on common fruit flies but the findings are interesting and have been debated a lot.
If seahorse is reproducing enough or on decline is difficult to say. I have been trying to find information but it looks like the data is inconclusive. It is rare to find underwater – even when diving in areas where they are present. They curl the tail around seaweed or small branches and are almost impossible to spot. This makes finding one to photograph even more thrilling.