Everybody loves seahorses, a firm favourite of many divers are the pygmies, which can be incredibly hard to find, not only because they’re so small but also because they’re so well camouflaged.
There are around 50 species of seahorse that live in tropical and temperate water all over the world. Seahorses prefer shallow water and they are usually located near coral reefs, mangrove forests or near seaweed. Many species of seahorse are endangered due to overfishing (seahorses are used in traditional Asian medicine) and destructive fishing practices such as using dynamite or other explosives. Other factors that negatively affect their survival are pollution of the ocean and global climate changes which decrease number of coral species and alter the temperature of the water.
Most seahorses, regardless of their size, share a number of common features; click on the headings below to find out more.
They rank among the slowest fish in the ocean; the dwarf seahorse is the slowest known with a top speed of 1.5 m per hour.
Seahorse mating starts with a courting process wherein the male seahorse “dances” and squirts water from his pouch to show the female that it’s empty. This can go on for a few days before mating takes place. Some species of seahorse are monogamous (they mate for life), while others stay together only during a breeding season.
It’s the male seahorse that carries the eggs to term, during mating, the female injects the eggs into the male’s pouch, where he fertilizes them. Pregnancy lasts between two and five weeks and young seahorses look like miniature versions of their parents. Sadly only 1% of babies will live long enough to reach the adulthood.
Seahorses can change colour; they do so either as camouflage or as a sign of stress. So if one changes colour while you’re observing it, then it’s time to back off.
Seahorses have equine (horselike) shaped heads, an elongated body and a curled tail. They use their prehensile tails to support themselves by wrapping around coral or seaweed. They do not have scales but despite their specific body shape, seahorses have gills, swim bladder and fins, just like all other fish.
The genus name for seahorses is Hippocampus, which comes from the ancient Greek hippos, meaning “horse” and kampos, meaning “sea monster.” There are around 50 species of seahorses, though as individual animals vary so much in appearance it can be difficult to identify their subspecies.
Seahorses use camouflage and patience to ambush prey, such as small crustaceans, as they come into range. Every time they ingest an item of food they make a clicking sound, which is also how they communicate with each other. Baby seahorses are known as fry and while growing can eat up to 3,000 items of food a day. By adulthood this number drops to around 50.
Seahorses have good vision and can move their eyes independently of each other, like a chameleon. They can simultaneously look in front and behind, which is helpful for catching prey and as a defence mechanism.
The lifespan of most seahorse species is between one and five years both in the wild and in captivity.
The biggest threat to seahorses comes from humans. They’re killed for use in Chinese traditional medicine, for souvenirs, or by shrimp trawlers. They’re also popular for the pet trade. It’s estimated that humans kill around 150 million seahorses a year.