The ocean has always been a place of mystery. Even today, scientists know relatively little about the creatures who live in the deepest parts of the sea.
In the ancient world, this realm was even more enigmatic. Legends were told of strange creatures that had been sighted by sailors or seen in the distant past.
The legendary water creatures of Greek mythology were bizarre composite animals with the tails of fish but many attributes found on land as well. Without a way to investigate beneath the surface, people imagined that life in the sea was very much like life on land.
Many of these sea creatures, however, were inspired by real ones that were seen only in glimpses. Second-hand accounts and brief sightings furthered belief in some of Greek mythology’s unusual water creatures.
One of the most identifiable sea creatures in Greek art is the hippocampus. The fish-tailed horses were not, however, unique to Greece.
The Greeks shared their belief in underwater horses with many other cultures. They were probably inspired by the Phoenicians, but as far away as Scotland the Picts developed a similar creature.
The hippocampi were literal sea horses. They had the tails of fish but the heads and front legs of land-based horses. The most detailed images included green scales, fin-like manes, and sometimes wings.
The Greeks believed that Poseidon, the god of the sea, was also the creator of horses. It was logical, therefore, that he would have made a race of horses that was suited to his own realm in addition to those that ran on land.
There was a more practical reason that the Greek people and those of other cultures believed in horses that lived beneath the waves, however.
They believed that the hippocampi were born the adult form of the seahorses we know today. People only saw small seahorses because they were faster and dove deeper as they grew to their full size or, according to some naturalists, migrated to the seas near India or Africa as they reached maturity.
In Greek and Roman art, the hippocampi appear often in the same context as familiar horses. They pull chariots and act as mounts for sea gods and nymphs.
The hippocampi were the most well-known and frequently represented hybrid water creatures, but an entire world of legendary animals was thought to mimic the environment of the land.
Underwater versions of many animals were imagined, including bulls, lions, leopards, and even elephants. The aigicampus, which was half-goat and half-fish, provided the basis for the constellation Capricorn.
Closely related to the hippocampi were the ichthyocentaurs, or fish-centaurs.
The word ichthyocentaur was not used by Greek writers, although it comes from their language. While the term was not used until the 12th century, images of these creatures appeared from at least the 2nd century BC.
The ichthyocentaurs had the same fish tails and equine legs as the hippocampi. Like traditional centaurs, they also had a human torso, arms, and head.
On the Pergamon Altar, the earliest known representation of the creatures, the ichthyocentaur is shown with wings as well. The shape is similar to the wings often shown on other legendary water creatures and is thought to be based on seaweed or fins.
Many times, the ichthyocentaurs were shown with horns or crowns that resembled lobster claws as well.
Most images show two ichthyocentaurs. They are identified as Aphros and Bythos, the gods of the sea foam and the depths.
Little is known of these two gods outside of what can be gleaned from images of them. They are sometimes associated with Aphrodite, which may have given Aphros his name, and may have been thought of as her teachers similar to the way the centaur Chiron was portrayed in the myths of other gods.
One Roman mythographer indicated that the ichthyocentaurs may have been inspired by foreign sea-gods. He claimed that Aphros and Bythos were revered in Syria where they were honored by the local equivalent of Aphrodite/Venus for their care of her when she was born in the sea.
Some of the most famous legendary water creatures of Greek mythology were the cetea. These sea monsters played a major role in many well-known myths.
They were usually shown as massive, serpentine creatures with rows of sharp teeth. While some images are more fish-like, many resemble dragons from other cultures.
The cetea were servants of the sea-gods, particularly Poseidon. They seemed to be friendly and gentle with the gods and nymphs of the sea, but could be menacing monsters as well.
In the Iliad, for example, Homer says that the cetea came up from the depths to play in the path of Poseidon’s chariot. In the Odyssey, however, the shipwrecked titular character feared that the sea god’s hatred of him would cause Poseidon to send a cetus to attack him when he was adrift.
While the cetea are often shown in art as the mounts and companions of sea nymphs, they are most famous in mythology for their attacks.
The Ethiopian Cetus, for example, was sent by Poseidon to punish that kingdom for its queen’s thoughtless words. When Cassiopeia bragged that her daughter, Andromeda, was more beautiful than the Nereids, Poseidon defended the nymphs’ honor with a sea monster.
Along with a floor, the sea monster ravaged Ethiopia until Andromeda was offered as a sacrifice. She was only saved when the hero Perseus, who happened to be passing by as he returned from slaying Medusa, killed the monster and rescued her.
A similar monster was sent by Poseidon to punish the city of Troy.
The god of the sea had been ordered to help build the city’s walls as a punishment for rebelling against Zeus. King Laomedon, however, refused to pay him for the work.
Like the Ethiopians, the Trojans decided to sacrifice a princess to save their kingdom from the sea monster’s attacks. King Laomedon, however, was not as willing to sacrifice Hesione as Andromeda’s father had been.
Heracles offered to rescue her in exchange for the king’s invincible horses, which had been given to the king by Zeus. Once again, however, Laomedon refused to pay and Heracles later returned to sack the city and kidnap the princess.
Like the hippocampi, the cetea are also believed to have been inspired by real creatures.
The term cetus was used to refer to nearly any large sea creature. Whales and sharks likely inspired the idea of huge, terrifying water creatures.
One cetus, for example, was described as having a broad, flat tail and lifting its head out of the water often to watch passing ships.. Others made baleful mourning sounds. Both of these are consistent with whales.
The size of whales likely read to rumors of their ferocity, particularly since sharks were often grouped in with the cetea as well. They were imagined, like many other monsters, to attack the kingdoms of the Greek world as a sign of the gods’ disfavor.
Some historians believe that accounts of the cetea attacks may have originated with tsunamis and earthquakes in the region. Natural disasters passed into legend as monster attacks that were accompanied by floods and destruction.
The ancient Greeks believed that the realm of Poseidon was, in many ways, similar to their own. Because of this, the legendary water creatures that they imagined living there were in many ways based on those found on land.
The hippocampi, for example, were the horses of the water. Although they had fish tails, they served the same function as the familiar horses of the earth.
Some legendary sea creatures were similarly inspired by legendary creatures and demi-gods of earth. Because centaurs were supposedly found on land, it seemed logical that they could be found in the sea as well.
Often, sea creatures in mythology blended elements of the real and the legendary. The cetea, for example, were likely inspired by sightings of whales and sharks but had the behaviors of the great serpents and dragons in other legends.
These legendary water creatures lived alongside the gods and nymphs that mirrored those on earth. The court of Poseidon and the creatures of his realm were mysterious, but also familiar to the people of the Greek world.