The Hippocampus from Mythology – Its name & meaning

You have probably seen cute pictures of cat mermaids all over the internet. But one creature I personally find to be much more intriguing is a creature with the upper body of a horse and a fishtail like a mermaid.

A horse with a fishtail is called a Hippocampus. The word comes from Greek mythology and literally means horse (hippos) and sea monster (kampos) which is often translated as sea-horse.

But what exactly are these magestic horses and what does their name tell about them?

The hippocampus: the half-horse half-fish creature from Greek mythology

The hippocampus is a seahorse in Greek mythology which is half horse and half fish and is associated with the gods of the sea. Hippocampi are the ones that pull Poseidon’s chariot through the ocean.

They were often depicted in art over the centuries and since the time of ancient Greece their appearance did not change much except for the fact that that they were not drawn with a fish tail in the very beginning.

Sometimes they were depicted with flippers instead of hooves or with wings in addition to their fish tails. One example of such a depiction of winged hippocampi are the seahorses on the famous Trevi Fountaine in Rome.

The word hippocampus was actually adopted into English from the Latin “hippocampus”. And the Latin form was originally derived from the Greek “hippokampos”, which is comprised of the Greek words “hippos” (ἵππος) for horse and “kampos” (κάμπος) for sea monster.

“Hippos” is by the way the same word as in “hippopotamus” which literally means “river horse” from ancient Greek “hippos” (horse) and “potamos” (river).

Besides pulling Poseidon/Neptun in his chariot these fish-tailed horses were also ridden by the sea nymphs – the so called nereids which are basically a kind of mermaid.

Poseidon is actually the god of horses, besides the sea and earthquakes, because he is the one that created the horses out of the ocean waves in an attempt to create the most beautiful animal on earth, thus making them his loyal followers.

Because it was created out of the ocean waves, the hippocampus symbolizes the power and beauty of the sea as well as the connection to the Greek gods and mermaids – the sea nymphs (naiads) – who looked over the ocean and saved drowning people with them.

Generally speaking, the hippocampi are described as trustworthy and beautiful creatures that mostly lived secretive lives in the ocean while sometimes interacting with the Greek gods and sea nymphs. To sailors they were seen as good omens like the sea nymphs.

They should not be confused with other mytholgical water horses like the Scottish Kelpie and similiar creatures from Scandianvia though, because these are mostly evil and live in rivers and lakes instead of the ocean.

The hippocampus is not the only animal from Greek mythology that has a mermaid tail though. Here is an overview of the half animal half fish creatures:

Mythological creatureGreek Name
Fish-tailed horseHippokampos
Fish-tailed lionLeokampos
Fish-tailed bullTaurokampos
Fish-tailed leopardPardalokampos
Fish-tailed goat Aigikampos (= Capricorn)
Creatures with a fish tail from Greek mythology. Notice that in Greek it is “kampos”. Today we hower use the the latin form “campus”.

So all of these were an animal in the front and a sea monster (kampos) in the back. The most famous one is probably the Aigikampos which is the Capricorn we refer to in zodiac signs today – basically a goat with fish tail – or a goat mermaid, however you like it.

The namesakes of the hippocampus

The hippocampus actually shared its name with the small seahorses that live in the ocean as well as the structure in the brain that is responsible for our memories.

Let’s have a closer look into what they have in common with the hippocampus from mythology.

Why are seahorses called hippocampus?

Seahorses belong to the biological genus Hippocampus. (Photo by Val Pierce on Unsplash)

The small fish called seahorses are scientifically classified in the genus Hippocampus with 46 species of seahorses in total.

The reason seashorses are called hippocampus is because they look like a fusion of horse and fish just like the hippocampi from Greek mythology, which literally are “horselike” (hippos) “sea monsters” (kampos) as well.

It is even said that ancient Greek people believed the hippocampi from Greek mythology were the adult forms of the little seahorses that we all know to be the cute little horselike fish.

Even though they share their name with the magestical sea-horses from Greek mythology, they are not quite as fast and strong.

Funnily the slowest fish in the ocean (according to Guiness World Records) actually is a seahorse species: the dwarf seahorse (Hippocampus zosterae) which lives in the Bahamas and parts of the Unites States. It only reaches an average length of 0.8 inches (2 cm) in length and the fastest it can move is about 5 feet (1.5 m) per hour.

Seahorses are very poor swimmers in general. With their body they cannot move easily in the water streams like other fish. Instead they swim upright using their dorsal fin (on their back) to propel and their pectoral fins (on the sides) to steer.

But they found another way to get around. They just use their tails to hold onto any small objects that float around in the ocean and take a free ride whereever they like.

Why is the hippocampus in the brain called that?

The hippocampus is also a brain structure that somewhat looks like a seahorse. (Picture by OpenClipart-Vectors on Pixabay, edited)

The hippocampus is not only a word for sea horses. In the brain there is also a structure which is called hippocampus. It is located right in the middle of the brain a little bit over your ears – on both sides. So you basically have two hippocampi or sea-horses in your brain.

The hippocampus is called that because the scientist (Julius Caesar Aranzi) who discovered this structure in the brain, named it after the similar looking seahorses, which are also called hippocampus in Greek.

This was in 1587 when researchers started to find out more about the brain structure. Interstingly not everyone was happy with the name hippocampus though. It was often debated in the following centuries.

Even the researcher Aranzi himself at first thought it looked more like a silkworm instead of a seahorse. Over time, however, the term has become widely accepted.

The fuction of the hippocampus does however not have much to do with its seahorse exterior. It is part of the limbic system in the middle of the brain and is mostly responsible for our memory especially for the saving of information to the long-term memory as well as spatial memory for navigating.

What does the name Hippocrates mean?

After all the “Hippos” and Seahorse talk I was wondering if hippocampus means “seahorse” and hippopotamus “river horse”, then what kind of horse is Hippocrates – the famous physician from ancient Greece?

But turns out the so-called Father of Medicin was not really called a horse. Instead, his name refers to “horsepower” because “hippos” (ἵππος) means horse, as we know by now, and “kratos” (κράτος) means power.

I hope you enjoyed this dive into the the world of the “horse mermaids” and the meaning of their name – hippocampus.

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