Who was the hippocampus?
The hippocampus was a half-horse, half-fish mythical sea creature in Greek mythology. It was associated with the god Poseidon and was responsible for pulling Poseidon’s seabound chariot.[1]
What powers does the hippocampus have?
The powers of the hippocampus are not explicitly stated in mythological records. However, it displayed impressive physical strength by pulling Poseidon’s chariot.
Where was the hippocampus located?
The hippocampus was located in the Aegean Sea, where Poseidon is recorded as having an undersea palace.
When was the hippocampus discovered?
The anatomical hippocampus was discovered in 1587 by Giulio Cesare Aranzio and noted for the first time in his work, Anatomicarum Observationum Liber (Book of Anatomical Observations). He described it as having the appearance of a “seahorse” or a “silkworm.”[2] In mythology, the hippocampus first appears in Homer’s Iliad.
Why did Poseidon create the hippocampus?
It is not explicitly stated that Poseidon created the hippocampus. However, Poseidon was famously connected to horses, as the “Tamer of Horses” and the father of Arion and Pegasus.
How did the hippocampus originate?
The hippocampus first originated in literature in Homer’s Iliad, wherein it is described as the beast that pulls Poseidon’s chariot in teams of two or four, depending on the source. It likewise appears in art from the Late Period of ancient Egypt and in Celtic, Etruscan, and Phoenician traditions.[3]
Table of Contents
Origins and Meaning of the Hippocampus
The hippocampi first appear in written records in the eighth century BCE in Homer’s Iliad. In this early depiction, the creatures are described simply as fish-tailed beings that pull Poseidon’s chariot.
The term hippocampus itself, derived from the Greek words hippos (horse) and kampos (sea monster), gained widespread use during the Roman period. The hippocampus was part of a larger tradition of fish hybrids in ancient Greek folklore, alongside creatures such as the taurocampus, leocampus, and aegicampus.
Within maritime religion in classical antiquity, the hippocampus and other aquatic beings and deities took precedence.[4] This prominence stemmed from their immediate relevance to coastal communities, who saw them as more directly beneficial than other, far-off deities. While the hippocampi were never directly worshipped in ports or at sea, they were revered as extensions of Poseidon’s will.
The Appearance of the Hippocampus in Mythology
The hippocampus is described as a hybrid between a horse and a fish: a literal “sea horse.” They had an equine upper body, and from the chest down, they had a scaly, serpentine fish tail. More often than not, they also had large fins that some artists interpreted as wings.
In Apollonius of Rhodes’s Argonautica, the hippocampi are described as possessing golden manes. Homer asserts them as being “bronze-hooved” (i.e., wearing bronze horseshoes) and “swift-flying.” Other ancient sources maintain that the hippocampi have uniquely blue eyes, reinforcing their deep connection to the sea. The hippocampi’s impressive form was immortalized in mosaics, frescoes, sculptures, and pottery throughout the ancient world.
Given their role as powerful beasts capable of pulling Poseidon’s chariot across the watery realms, it’s no surprise that their most notable traits were their immense strength and speed. While these legendary animals were usually the mounts of Poseidon or other sea-related gods and goddesses, they were often allowed to roam freely in the seas when not yoked to the chariot.
The Role of Hippocampus in Greek Mythology
In Greek and Roman mythology, the hippocampus was a fantastical sea creature that symbolized the kinetic energy of ocean waves. Known for their role as pullers of Poseidon’s chariot, the hippocampi were also revered as saviors of sailors akin to the Oceanids and the Nereids. These creatures embodied the power and majesty of the sea, reflecting its untamed and unpredictable nature.
The hippocampi are consistently described with awe and fascination in the myths they inhabit. More than just vital attendants to Poseidon, they were often depicted as guardians, guides, and protectors in their own right. For instance, in the Argonautica, a hippocampus helps guide Jason and the Argonauts back to the sea after they traverse a desert in Libya. Jason emphasizes the swiftness of the hippocampi when he tells his crew how Amphitrite, Poseidon’s wife, had just unyoked these magnificent creatures from their chariot when they appeared to aid the heroes.
Hippocampi are also frequently depicted as attendants to other deities connected to the sea, such as Amphitrite, Aphrodite Pelagia (of the sea), Orion, the Nereids, and the Oceanids. Beyond their allegiance to Poseidon and the oceanic gods, they are also seen as companions to freshwater deities, including Oceanus and Tethys, further suggesting their connection to the sea and freshwater realms. Their unwavering loyalty to Poseidon is especially evident as they accompany him on his numerous journeys across the oceans.
Representation in Ancient Art and Culture
The hippocampus has long been a fascinating figure in ancient art, since it represents the fusion of terrestrial and aquatic realms. Most often depicted with the upper body of a horse and the lower body of a fish, the hippocampus has appeared across various ancient cultures, most notably in ancient Greek art, Egyptian, and Roman art. It was also featured in coinage from Phoenicia and Italy.[5]
In ancient Greece, the creature’s prominent role in Greek mythology made it a common motif in Greek art, especially in mosaics and frescoes in baths and near springs. It was also commonly depicted in Greek black-figure and red-figure pottery.
On surviving Attic pottery, these creatures are typically shown as powerful animals, with their fish tails blending seamlessly with their equine forms. The most famous depictions of the hippocampi are scenes of Poseidon riding his chariot.
In Roman art, the hippocampus continued to be an important mythological symbol. Poseidon’s Roman counterpart, Neptune, was often depicted with his chariot pulled by hippocampi as well. They appeared in Neptune’s retinue in art from the Italian city of Pompeii to Aquae Sulis in England.
Although the hippocampus appears less frequently in Egyptian art than in Greek or Roman depictions, its mythological significance is evident in coffins and tomb walls from Egypt’s Late Period to the decline of Roman Egypt. Unlike in Greco-Roman art, where it is linked to sea gods, Egyptian representations align more with Etruscan beliefs, portraying the hippocampus as a psychopomp, a guide for the dead in the afterlife.[6]
The hippocampus was also associated with the Capricornus constellation. Although the “Capricorn” is an aegicampus—a fish-tailed goat—it has become the representative for other fish-hybrid animals in Greco-Roman myth.
The Hippocampus in Modern Culture
The hippocampus continues to inspire humanity and symbolize the majesty of the sea in modern culture. It has manifested in literature, art, and media, especially those exploring fantasy. They have also lent their name to one of the most crucial parts of our brains: the hippocampus.
In Literature
In contemporary literature, the hippocampus often serves as a mount for powerful or divine characters. For instance, in the Percy Jackson series by Rick Riordan, hippocampi play a major role in getting the titular character Percy and his companions safely from one point to another. In this iteration, they appear loyal and obedient to the characters descended from Poseidon: Percy and the young cyclops Tyson.[7]
Likewise, Roger Lancelyn Green’s novel Tales of Greek Heroes (1958) emphasizes the importance of the hippocampi as steeds and beasts of burden of Poseidon.
In Art and Film
In the realm of art, the Flemish naturalist and artist Anselmus de Boodt (1550–1632) gave his own interpretation of the hippocampus sometime in the sixteenth century. Depicted as an unusual mythological creature with a golden mane and peculiar, three-clawed hands in the place of cloven hooves, de Boodt’s hippocampus is one of its kind. Other famous artworks of the hippocampus include the winged hippocampus sculpture at the Trevi Fountain and a stylized 1937 fountain in Kansas City, Missouri.
The hippocampus has also been captured in movies, especially in film adaptations of Riordan’s Percy Jackson novels and Homer’s Iliad and Odyssey. In such films, they are depicted as colorful, striking creatures loyal to Poseidon. Other films, such as Aquaman and the Lost Kingdom (2024), show the hippocampus as the steed of the celebrated DC superhero while he is underwater in Atlantis.
In Neuroscience
Interestingly, the term hippocampus also refers to a critical part of the brain involved in memory formation and spatial navigation. While this is a completely different meaning from the mythological hippocampus, it reflects how deeply the name has permeated modern science and language.
The hippocampus in neuroscience plays an essential role in learning and memory. It was named hippocampus because of how similar it looked to a seahorse; an alternate name for the hippocampus is cornu Ammonis (“Ammon’s horn”), which refers to the ram-horned Egyptian god Ammon.
Other Sea Creatures Related to the Hippocampus
The hippocampus was one of many sea creatures in Greek mythology. They were just the only ones to specifically resemble a horse. To the ancient Greeks, the seas were filled with mythical creatures who fulfilled various roles:
- Icthyocentaurs
- Tritons
- Proteus
- Nereids
- Nerites
- Oceanids
More sinister sea creatures also lurked beneath the waves. Scylla and Charybdis were also subservient to Poseidon—just a lot scarier than those listed above:
Sea creatures often appeared in myth as a way to explain the mysterious workings of the ocean. They were the force of waves and currents and were equally responsible for the security of a ship and its sailors as Poseidon himself was.
Wrapping Up the Tale of Hippocampus
The hippocampus, with its unique blend of equine and aquatic features, has fascinated humanity for eons. Nowadays, our first thought may be the name of a significant part of our brain, but as it turns out, that little seahorse-like structure has some epic origins.
Whether in ancient mythology, art, or contemporary works, its legacy continues to symbolize the balance between the known and the unknown. The hippocampus has ultimately become an enchanting symbol of strength and majesty, one that is identifiable across culture and time.
References
- Kline, A. S., trans. 2009. “BkXIII:1-80 Poseidon rouses the Aiantes.” In Homer: The Iliad. https://www.poetryintranslation.com/PITBR/Greek/Iliad13.php.
- Engelhardt, Eliasz. 2016. “Hippocampus Discovery First Steps.” Dementia & Neuropsychologia 10(1): 58–62. https://doi.org/10.1590/S1980-57642016DN10100011.
- O’Brien, Louise, and Chang Lu. 2024. “Hybrid Creatures in Late Period Egypt: The Hippocampus.” Garstang Museum of Archaeology. https://garstangmuseum.wordpress.com/2024/04/11/hybrid-creatures-in-late-period-egypt-the-hippocampus/.
- Brody, Aaron J. 2008. “The Specialized Religions of Ancient Mediterranean Seafarers.” Religion Compass 2, no. 4 (July): 444–454. https://doi.org/10.1111/j.1749-8171.2008.00079.x.
- FORVM Ancient Coins. n.d. “Hippocamps on Ancient Coins.” FORVM Ancient Coins. Accessed March 26, 2025. https://www.forumancientcoins.com/catalog/roman-and-greek-coins.asp?vpar=1811&pos=0&sold=1&srsltid=AfmBOorTzsbcOMh-6J8o_p2xAsq5TW-sjaXibyP2UPRjCD7rcJ-NHAz0.
- Tuck, Steven L. 2018. “Guarding the Underworld: The Warrior and Hippocampus Motif in Etruscan, Lucanian, and Roman Art.” In The Classical Journal. The Classical Association of the Middle West and South. https://camws.org/sites/default/files/meeting2015/Abstracts2015/254.GuardingUnderworld.pdf.
- Fandom. n.d. “Hippocampus.” Riordan Wiki Fandom. Accessed March 26, 2025. https://riordan.fandom.com/wiki/Hippocampus.