In this episode of “Take a Minute to Relax”, we invite you to look deep into the eye of one of the most effective and successful hunters, not only of the aquatic realm but of the entire planet: Hippocampus histrix, a fish that also goes by the common name of Spiny or Thorny seahorse.
The meaning of Hippocampus histrix
Their scientific genus name “Hippocampus” is derived from the Greek words “Hippos & Kampos”. “Hippos” means horse, and “Kampos” means sea monster. The Romans later adopted it as “Hippocampus”. In both Hellenistic and Roman imagery, it was depicted as a two-hoofed horse creature with a fishtail, that drew the “chariot” of the sea god Poseidon/Neptune. Looking at the creature, it’s not too hard to understand why science adopted the “Hippo” part of its name, but the “Kampos” (sea monster) part, seems a bit far fetched at first. Also, histrix is rooted in ancient Greek and means spiny.
Look and learn all about the Thorny Seahorse (Hippocampus histrix)
With their elongated bodies, covered in an armour of bony plates, and prehensile tails, they look nothing like any of the traditionally shaped fishes. However, equipped with fins for propulsion, gills for breathing, and even a swim bladder to control their buoyancy, these oddly shaped creatures are indeed fish from the family Syngnathidae. They usually can be found in shallow tropical-, and temperate waters, but also do occur in some colder water in places like New Zealand, Argentina, and Canada.
Their usual lifespan ranges between 1-5 years. But there’s a lot more to this creature, than just its strange appearance. To say that seahorses are not very good swimmers, would be somewhat of an understatement. Their main source of propulsion is delivered by a small fin on their back, that although it can flutter up to 50 times a second, gives them very little speed. They’re however capable of covering large distances, by simply using their prehensile tail to hang onto pieces of seaweed and/or debris, which can carry them to far of places.
Killing for living: Thorny Seahorse (Hippocampus histrix) same as other species of seahorses
Hippocampus does neither possess any teeth, nor stomach! Therefore, the food they consume passes through their system so quickly, that they have to eat almost constantly, in order to survive. Their diet consists of plankton, plants, small fishes, and crustaceans, like shrimps and copepods. Adults will typically have between 30-50 feeding sessions a day. Baby seahorses are called “fry”, and like the teenagers of our own species, can consume an incredible amount of food. Their food intake can be an astonishing 3000 food pieces a day!
The eyesight of seahorses is excellent, and they are able to move their eyes independently from each other, making it easier to spot their food, whilst using their tube-like snout as a suction device! Due to their lack of movement, and ability to blend in with their environment, their tiny prey has no idea of their presence, until it’s too late. They have one of the highest success/kill rates of any creature in the animal kingdom. 90 %, compared to say lions with a 25%, and even sharks are well below 60%.
Love for life: Not only with Thorny Seahorse (Hippocampus histrix)
Hippocampus are essentially serial monogamists and stay with one partner for as long as possible. They also have voices and can make grunting sounds, as well as clicking noises. Some of these noises are made on a couple’s daily romantic “confirmation dance”, that takes place each morning, whereby the couple dances and pirouettes together for a couple of minutes. This often results in the iconic heart-shaped pose of their heads and upper bodies, before they separate for the rest of the day.
They have this morning ritual to confirm the other partner is still alive, reinforce their bond and synchronize their reproductive cycles. After courtship, the female deposits her eggs in a specialised breeding pouch of the male, where he fertilises them. This “male pregnancy” lasts between 10-25 days, depending on the species.
The number of young released by the male seahorse at the end of term, are on average between 100–1000 babies. Under normal circumstances, less than 1% of these will ever make it to adulthood, which explains the large number of offspring. Whilst the male is taking care of the “pregnancy“, the female can use her energy into producing the next batch of eggs.
Hide and seek
Seahorses can not only change the colour but even the texture of their skin. Not just for camouflage purposes, but also to communicate and express their emotions. They do this by contracting or expanding pigment cells known as chromatophores. These muscle manipulated cells can be controlled by the nervous system, for quick changes in appearance, or by hormones for slower more flamboyant changes. On top of that seahorses are masters at the game of hide and seek. They have for instance figured out that humans often manage to find them, because of their iconic horse-like body shape, and therefore often lay down flat on the bottom, in order to remain hidden.
What an incredible creature this is!