Top of page

The Great American Sea Serpent

Share this post:

A large snake-like animal with a dorsal fin and whisker-like filimants on its headon a rocky beach.
The great sea-serpent, found in Hungary Bay, Bermuda, on January 22, 1860,” illustration based on a sketch by W.D. Munro. Harper’s Weekly, v. 4, no. 166 (1860 March 3), p. 132. Prints and Photographs Division, Library of Congress.

The 19th century saw an explosion of interest in sea serpents as well as other mysteries of nature in the United States and Europe. This was the dawn of an age when legend met science with the idea that science could solve ancient mysteries. One could say that we are still in that age, although the technology we have to tackle the problem now far outstrips what was available then. In the Atlantic there arose the idea of a single beast, “the great American sea serpent.”

Tales of sea serpents may be among the oldest stories of humankind, told in many parts of the world.  Sea snakes are real animals, found in the Indian Ocean and southern Pacific. The longest can grow to about nine feet — impressive enough to give rise to legends.  Although some of these snakes are venomous, they usually do not pose a threat to humans. Large and venomous land snakes could also be part of the inspiration for tales of snakes in the sea. But reptiles do not do well in cold waters and, even on land, reptiles tend to be smaller in temperate climates with larger species found in the tropics.

Ryu Shoten,” by Gekko Ogata, 1897. A sea dragon ascends to Mount Fuji. Prints and Photographs Division, Library of Congress.  In ancient Japanese tales, this was a god that could take human form. In some depictions it has feet like a land dragon, while in others it does not.

The source of European sea serpent legends is often thought to be Scandinavian myths and tales. Folklorists have seen these as part of Indo-European history, since tales of magical sea serpents and dragons have similarities to myths from South Asia.  More recently, DNA studies have revised and improved upon our understanding of early migrations, showing that peoples traveling out of Africa went farther east and south than was previously imagined.[1]  These migration patterns suggest the possibility that the tales of sea serpents in other parts of the world are also related, with the Norse sea serpent, the South Asian Naga, the Japanese Ryujin (sea dragon), and the Tizheruk of Inuit lore all inspired by stories of real large land snakes and sea snakes of South Asia. The great Naga god of the oceans is responsible for the tides, floods, and waves, and so is the great sea serpent of the Norse tales. An idea that there is a gigantic sea serpent that rules the rest is a part of south Asian and Norse myths and of the Japanese ocean Ryujin as well.

These connections are tempting but difficult to prove. Some features of sea serpents as they have come to be known today may have other connections as well, those of sea creatures that may be found in places that the true sea snakes are not.

As Americans and Europeans of the 19th century considered scientific approaches to sea serpents, they still carried many ideas about sea serpents that colored their observations and reactions. From early times sea serpents were seen as monsters that could attack ships and eat sailors. They were also thought of as reptiles. It took some time before doubts were raised about these basic assumptions. Stories and beliefs about sea serpents, together with the difficulties of seeing an animal clearly in the ocean waves, especially at a distance, colored the observations of witnesses. Each sea serpent sighting could influence the way the next was perceived. Drawings and news reports by people who did not observe the incident directly could further influence observations and ideas about mysterious creatures of the sea.

Sea serpents as imagined in Europe in the early 17th century. Sea serpents in European countries were usually seen as dangerous, even evil; inclined to destroy ships and eat sailors. A woodcut print from Konrad Gesner’s Historiae Animalium, 1617-1621, v. 4, p. 1040. (This image is found in the Library’s Prints and Photographs catalog at the link.)

Beginning with a sighting of the Gloucester, Massachusetts sea serpent in August 1817, the idea arose that there was a sea serpent found in the Atlantic off North and South America. Gloucester legends had told of a strange monster on the coast from colonial times. An 1817 report of the Linnaean Society of Massachusetts summarized interviews with people who had seen it, including sightings from previous years. They proposed that it was a new species, Scoliophis atlanticus.[2] It was said to be a dark sinuous animal that moved vertically up and down in the water like a caterpillar. But actual reports of observers varied a great deal. Witnesses on the shore said it resembled a long line of barrels, riding high in the water. Those who saw it from ships reported a snake that was dark with a head like a horse. Subsequent drawings of it varied a good deal. Captain  Joesph Woodward of the schooner Adamant reported an encounter off the coast of Cape Ann in May, 1818. He said he shot a cannon at the monster. He was quoted as saying that after the cannon shot:

The serpent shook its head and its tail in an extraordinary manner and advanced toward the ship with open jaws; I had caused the cannon to be reloaded, but he had come so near that all the crew were seized with terror, and we thought only of getting out of his way. He almost touched the vessel and, had I not tacked as I did, he would certainly have come on board. He dived, but in a moment we saw him come up again with his head on one side of the vessel and his tail on the other as if he was going to lift up and upset us.  However we did not feel any shock. He remained five hours near us, only going backward and forward.
— British Literary Gazette, August 1, 1818 (page 489)

Part of the excitement in the 1800s about the monsters of the sea was the idea that science could now explain what had once been myth and legend. Many attempts were made to explain the Gloucester serpent as a group of migrating whales or seals. Some proposed that an animal thought to be extinct might still be alive, such as long-necked ocean dinosaurs. People at the time assumed that there was just one “great American sea serpent.” But it is quite possible that the variety in the descriptions means that there was not one animal (or group of animals) but various accounts of different creatures or other natural phenomena. The other underlying assumption common to many sea serpent stories of this period, which is also found in Captain Woodward’s account, is that it was necessary to try to kill the animal. The concept of sea serpents as creatures that would attack boats and kill sailors continued to color people’s perceptions.

The ship HMS Daedalus with a large sea snake in the foregound.
The Great Sea Serpent seen from the HMS Daedalus. The crew of this ship encountered an unknown animal in August 1848. This drawing was made by an artist who had not seen the animal. Illustrated London News, October 28, 1848. (This image is available in the Prints and Photographs catalog of the Library of Congress at the link.)

One animal known to be regularly mistaken for a sea serpent or sea monster today is the basking shark. The second largest fish in the ocean, it is a strange and impressive sight.  They swim with their large mouths wide open just under the waves with a long conical snout just above the ocean surface — so the nose can be mistaken for a snake’s head. They have several gill slits that nearly circle their necks, and so may appear as though they have a mane (as serpents are often said to). They are generally interested only in eating plankton, but when hunted they have sometimes attacked ships. They also may jump out of the water, presumably to rid themselves of parasites, and the sight of an enormous long-bodied fish jumping could no doubt be imagined to be a serpent rising out of the waves by a startled observer. So this fish is one example of a known animal that could inspire sightings like that described by Captain Woodward. The spines of dead basking sharks that occasionally wash up on shore have also been mistaken for sea serpents.

On the evening of August 6, 1848, a sighting of great importance to the modern history and lore of sea serpents occurred. The crew of the HMS Daedalus observed an “enormous fish” that was described by the crew as swimming past the boat with its head four feet out of the water while off the coast of Africa south of St. Helena Island in the South Atlantic. According to Captain Peter McQuahe it was dark with the “mane of a horse, or rather a bunch of seaweed washed about its back.”[3] The head was described as flat and snake-like.  In spite of the location, this was also thought to be the same “Great Sea Serpent” seen off the coast of the Americas. A drawing made for British newspapers showed a giant snake with a round head and no mane, but this became the image most widely associated with this sighting. At the time, a common scientific explanation was that this was a seal or sea lion mistaken for a snake.[4] Some proposed that it was a long-necked seal of an unknown species.[5] This mysterious seal was also later proposed as the animal seen in Loch Ness. Others proposed that it was a plesiosaur that had failed to go extinct, although there were scientists who quickly tried to dismiss this idea.[6] These ideas, based on an inaccurate drawing, have entered folk culture and cryptozoology. They endure because of the problem that in many sea serpent sightings the animal is said to hold its head well out of the water, which is unlikely without a body to support the head. Other theories of the Daedalus sighting, based on witness accounts, are that it was some species of baleen whale and the “snake head” was actually the top of the animal’s mouth. This is plausible if the report of the mane is discarded. It might also have been a basking shark, if the report of the head held four feet above the water is discarded. It is difficult to name a known animal that completely fits the witness accounts, so the mystery continues to perplex those interested in monsters of the sea.

An artist’s drawing of the hypothetical long-necked seal proposed to be the animal encountered by the HMS Daedalus. “An Eminent Scientist Says the Sea Serpent is a Seal,” in the San Francisco Call, July 11, 1897, p. 19.

In January 1860 yet another face was given to the American sea serpent, as an astonishing animal washed up on Hungary Bay in Bermuda. It was drawn by an observer, W.D. Munro, and so the artist’s rendition of his sketch (at the top of this article) was likely truer to life than in the case of the Daedalus sighting.  It is, in fact, a recognizable species, the giant oarfish or ribbon fish. Even today, news stories about encounters with giant oarfish often call them “the real sea serpents.” Unlike most fish, they do not have scales. Their dorsal fin and sensory organs that spring as hair-like filaments from its head, are bright red. Two red oar-shaped sensory organs also grow from it’s pectoral muscles, giving it its name. It is thought to be the longest bony fish with well-documented specimens about thirty feet long and some longer reported.  Historic sightings of sea serpents with red manes might well have been sightings of this unusual fish. They are deep water animals of warm seas and are rarely sighted except when they are dying or dead.   In 1897 one was captured alive off the coast of Australia and sent to a German aquarium.[6]

News paper page with an article and drawings of various sea serpents.
The Sea Serpent is a Fact,” a story published in the Washington Times, April 24, 1904, with illustrations that showcase many of the famous sightings from the 19th century. In Chronicling America (Library of Congress) with a full-sized page image at the link.

Another animal that may have influenced the image of sea serpents, and perhaps Asian dragons as well, is the frilled shark.  Some descriptions of serpents with a mane and a horse’s head may be this animal. It is another deep sea fish with a sinuous body and an astonishing boxy head with many gills resembling a mane.  They are found in the deep sea in the north Atlantic, the coast of the United States and in the seas around Japan as well.  Some commonalities of sea serpent legends of Asia and Europe may be due to encounters with this shark. It is only seen near the surface if sick, dead, or dying and is no threat to humans in spite of its fierce appearance.  The Japanese print of the Ryu Shoten above shows a flat-headed serpent with frills at its neck that might be inspired by frilled sharks.

In 19th century accounts in newspapers, the entertainment aspect of news about sea serpents is very apparent. In a time before television, these stories were often written so that they could be read aloud and the narrative of sightings often resembled adventure stories.

Many of the ideas formed about sea serpents in the 19th century with the problem of the great American sea serpent were brought into the 20th and some are still with us today. Some of these 19th century ideas are cleverly brought together in a Washington Times article, “The Sea Serpent is a Fact,” from April 24, 1904, (available via Chronicling America and the link on the above image).  A fanciful drawing of a giant oarfish dominates the page, accompanied by depictions of sea serpents sighted during the past century. Notice the plesiosaur at the bottom of the page. The vigorous life of the theory of surviving ancient creatures can be seen in “Possible Sea-Serpents: Prehistoric Monsters that May Not be Extinct,” by Frederic A. Lucas, Director of the Brooklyn Institute of Arts and Sciences. New-York Tribune Sunday Magazine. (New York, NY), 18 June 1905, page 5 (also found in Chronicling America).

There are discoveries to be made in the ocean still, particularly in the deep ocean.  There may be species of animals once described as sea serpents that have not been discovered yet. The true sea snakes seem to be moving northward with warmer waters so that they are being encountered by people who have never seen them before. Three yellow-bellied sea snakes washed up dead on southern beaches in California in 2015 and 2016, far north of their normal range.   If you should see something strange in the ocean, appreciate it from a safe distance, and remember the long tradition of sea serpents that has been carried by humans wherever they travel on, in, or near the sea.


  1. For example, see the “Human Journey: Out of Africa” the Human Journey web site.
  2. Report of a committee of the Linnaean Society of New England, relative to a large marine animal, supposed to be a serpent, seen near Cape Ann, Massachusetts, in August 1817. Cummings and Hilliard, publishers, 1817.
  3. Captain Peter McQuahe was quoted in a number of articles at the time. See, for example. The Great Sea Serpent,” in Caledonian Mercury (Edinburgh, Scotland), Monday, October 23, 1848; Issue 19826.
  4. See, for example: “The Great Sea Serpent Tested and Found Wanting,”  Liverpool Mercury etc (Liverpool, England), Tuesday, November 21, 1848; Issue 2041, p. 738.
  5. An example is found in “An Eminent Scientist Says the Sea Serpent is a Seal,” in the San Francisco Call, on July 11, 1897, page 19, where a “French scientist,” A. Labbie, is quoted and a drawing provided. (In Chronicling America.)
  6. Sixteen-foot Long Monster of the Deep Captured Alive That Explains Sea Serpent Yarns,” The Herald (Los Angeles, California), October 17, 1897, Page 26 (near the bottom of the page). (In Chronicling America.)


Chronicling America: Historic American Newspapers, Library of Congress.

New York Journal and Related Titles, 1896 to 1899, Library of Congress.

Newspapers and Current Periodicals Reading Room, Library of Congress.

Comments (5)

  1. Fascinating article – very well researched and beautifully written. I’m sharing it!

  2. a good place to find things out about sea serpent

  3. The photos of this creature are wrong. I have seen this thing with my own eyes. Till recently I thought I was crazy till someone I was with told me they saw the same thing. So, year was 1999-2001 for got the year. Was on a small boat 5 miles outside Florida. This sea dragon about the roundness a basketball with black shinny skin like the creater off alien vs predator. It’s body was going up and down in the water like the stereotypical water dragon photos. It’s 2 inch spikes seemed dull, ran down it’s back and sides they matched the color of it’s skin. It kept its head under water, but you could see the body going up and down had to be around 40 or more feet.

  4. Just watched paranormal videos on discovery and a woman and man who live in Florida captured what appeared to me as a giant snake attacking a manatee. I googled “giant sea serpent” and found this. You can clearly see the smooth black skin William mentioned in his comment and it has a white under belly, and wrapped around its prey just like a snake would. At first I though perhaps a giant anaconda but the color is wrong. There aren’t reticulated pythons this dark of a contrast from back to belly, not even a morph created like it, so a pet reticulated released is debunked. This is 100% real, and two sightings off the coast in Florida is too coincidental. They should conduct a study and really see if they can’t find an ancient serpent who has remained illusive. Absolutely amazing to know this exists.

  5. I am fascinated by the idea of sea serpent though I ‘ve never seen one, based on my research I believe they may actually exist. Though sightings may be rear in this present day and age, it doesn’t mean they never existed. I am actually fascinated by the account of Captain Wooword in 1818 which was rendered with such details. Also, if fossils of dinosaurs have been unearthed then we should believe that such creatures may have actually existed and perhaps still in existence!

Add a Comment

This blog is governed by the general rules of respectful civil discourse. You are fully responsible for everything that you post. The content of all comments is released into the public domain unless clearly stated otherwise. The Library of Congress does not control the content posted. Nevertheless, the Library of Congress may monitor any user-generated content as it chooses and reserves the right to remove content for any reason whatever, without consent. Gratuitous links to sites are viewed as spam and may result in removed comments. We further reserve the right, in our sole discretion, to remove a user's privilege to post content on the Library site. Read our Comment and Posting Policy.

Required fields are indicated with an * asterisk.