A sea serpent is a kind of sea monster found in stories from different cultures and religious writings. Famous examples include the Mesopotamian Tiamat, the Ugaritic Yam and Tannin, the Judaic Leviathan and Rahab, the ancient Greek Cetus, Echidna, Hydra, and Scylla, the Vedic Vritra and Surasa, and the Norse Jörmungandr.
Mythology
The story of a powerful god acting as a hero to defeat a sea serpent appears in many ancient cultures, such as in the Near East and Indo-European myths. Examples include Lotan and Hadad, Leviathan and Yahweh, Tiamat and Marduk, Illuyanka and Tarhunt, and Yammu and Baal from the Baal Cycle. In the Hebrew Bible, large sea creatures are described as part of creation under Yahweh’s command, such as the Tanninim in Genesis 1:21 and the "great serpent" mentioned in Amos 9:3. In the Roman story The Aeneid, two sea serpents killed Laocoön and his sons after he opposed bringing the Trojan Horse into Troy. Claudius Aelianus wrote about a giant sea centipede in his book On the Nature of Animals, which had a tail like a crayfish and moved using many legs on both sides of its body. Guillaume Rondelet described a similar imaginary creature called a "centipede cetacean" in his work L'histoire entière des poissons.
In Nordic mythology, Jörmungandr (or Midgarðsormr) was a sea serpent or worm so long that it wrapped around the entire world, Midgard. Sea serpents also appear in later Scandinavian folklore, especially in Norway. For example, a story from 1028 AD describes Saint Olaf killing a sea serpent in Valldal, Norway, and throwing its body onto the mountain Syltefjellet. Marks on the mountain are linked to this legend.
Natural history
A witness account is described by Aristotle in his book Historia Animalium, which discusses natural history. Strabo mentions a report by Poseidonius, who saw a dead sea creature on the coast of the northern Levant. He wrote: "The first plain near the sea is called Macras. Here, as Poseidonius said, a dead dragon was found. Its body was about 30 meters or 100 feet long. It was so large that horsemen standing on either side could not see each other. Its jaws were big enough to fit a man on a horse. Each scale on its body was longer than a shield." This event happened between 130 and 51 BC.
Olaus Magnus, a Swedish writer and clergy member, included pictures of sea serpents and other sea creatures in his map called the Carta marina. In his 1555 book History of the Northern Peoples, he described a Norwegian sea serpent: "Sailors traveling near Norway say a serpent, 200 to 600 feet long and 20 feet wide, lives near Bergen. It comes out of caves at night to eat animals or swim in the sea to eat fish. It has long hair on its neck, black scales, and red eyes. It attacks ships and swallows people, rising from the water like a tall column."
Erik Pontoppidan, a Norwegian bishop who lived from 1698 to 1764, believed sea serpents existed but doubted they attacked ships or ate humans. However, sailors claimed sea serpents wrapped ships in their bodies and pulled them underwater. To protect their ships, sailors sometimes threw heavy objects like paddles or shovels into the water, hoping the serpent would take them instead.
Reverend Hans Egede, a Danish-Norwegian missionary, wrote in his journal about seeing a sea monster in 1734. He described: "The creature rose high out of the water, with its head above the ship’s mast. It had a long snout, spouted water like a whale, and had wide flippers. Its body had scales and wrinkled skin, and its tail looked like a snake. After some time, it sank underwater, leaving its tail visible far from its head." Egede noted the creature was seen at 64 degrees north latitude and was as thick as the ship and three to four times as long. A companion named Bing drew a sketch of the creature, which showed it had red eyes. Bishop Pontoppidan thought this was different from other sea serpents because of the red eyes and the shape of its fins.
Henry Lee, who translated Egede’s journal, suggested the creature might have been a giant squid, not a sea serpent.
In 1845, Albert C. Koch displayed a 35-meter-long skeleton in New York, claiming it belonged to an extinct sea serpent. However, Professor Jeffries Wyman, an expert in anatomy, examined the skeleton and found it was made from bones of different animals, including a whale.
On August 6, 1848, Captain McQuhae of the ship HMS Daedalus and his crew saw a sea serpent between the Cape of Good Hope and St. Helena. They described the creature as having 1.2 meters of its head above water and believed 18 meters of its body was underwater. The crew said the creature swam quickly and was visible for about 20 minutes. One officer compared it to a lizard rather than a serpent. Gary J. Galbreath, an evolutionary biologist, later suggested the crew might have seen a sei whale.
A report in the Illustrated London News on April 14, 1849, described a sea serpent spotted off the coast of Portugal by the ship HMS Plumper. On December 31, 1848, a sailor saw a long, black creature with a sharp head moving slowly near Oporto. Its back was about 20 feet above water, and its head was 6 to 8 feet long. Something on its back looked like a mane, but the creature soon disappeared into the distance.
Natural explanations
In 2016, R.L. France wrote a paper for the International Journal of Maritime History. The paper suggested that many sea serpent sightings, including reports from the 1800s of serpents attacking whales, were actually caused by people mistaking whales that were caught in fishing nets or floating debris.
Giant oarfish, which have long, slender bodies and swim in a wave-like motion, are also thought to be responsible for some sea serpent sightings. In 2016, an episode of the TV series River Monsters explored the origin of the sea serpent myth. The episode concluded that the oarfish was the most likely explanation for these sightings.
In a 2023 article for Fate, Karl Brandt proposed that famous sea serpent sightings might be explained by sperm whales that had been harpooned and were stuck to their hunters’ overturned rowboats. These boats could collect debris on the water’s surface, creating long, floating lines that appeared to move through the water. This idea was supported by the fact that most sightings in Norwegian fjords happened during the summer months of June to August, when sperm whales are most common.