Could the Loch Ness Monster Be a Giant Eel? A New Study Tackles the Mystery

Written reports of a monster in the vicinity of Scotland's famed Loch Ness first arose in the sixth century. Much earlier than that, some 1,500 years ago, an image of a strange, unidentifiable aquatic creature was carved on standing stones by the ancient inhabitants of the Scottish Highlands. While mentions continued through the centuries, it wasn't until the 1930s that purported sightings of the "monster fish" (also variously referred to as the "water beast," "sea serpent," "dragon," and similarly sensational monikers) captured the public's attention. The Loch Ness monster, also known as Nessie, has been featured in popular media ever since.

From a biodiversity perspective, as we try to understand the broad array of organisms on the planet, the discovery of such an extraordinary species would be enlightening, to say the least. And, of course, from a folklore and public interest point of view, unraveling the mystery of Nessie would make international headlines.

Science has been hot on the heels of Nessie. The 20th century saw systematic searches for the creature, complete with submersibles, sector-scanning sonar surveys, hydrophones, underwater photography, long-lining, and trawling. (Imagine being the one to accidentally kill the Loch Ness monster with fishing gear?)

Aside from physically seeking out Nessie, scientists have worked on a number of theories about the Loch Ness monster, one of those being the “eel hypothesis.” According to a new study analyzing the theory, the eel hypothesis "proposes that the anthrozoological phenomenon at Loch Ness can be explained in part by observations of large specimens of European eel (Anguilla anguilla), as these animals are most compatible with morphological, behavioral, and environmental considerations."

The new study, which was published in the journal JMIRx BioEel, explains that the eel has an elongated body form, a single pair of pectoral fins, strong musculature, a high-amplitude winding movement, and dark skin. With eyewitness descriptions of Nessie describing a dark creature with an elongated head-neck, pectoral fins, and extreme flexion, the eel hypothesis would certainly make sense.

However, while acknowledging the potential presence of large eels in the loch, the study concludes that "purely statistical considerations do not support the existence of exceptionally large eels."

"The chances of finding a large eel in Loch Ness are around 1 in 50,000 for a 1-meter specimen, which is reasonable given the loch’s fish stock and suggests some sightings of smaller unknown animals may be accounted for by large eels," write the author. "However, the probability of finding a specimen upward of 6 meters is essentially zero; therefore, eels probably do not account for sightings of larger animals."

“In this new work from the Folk Zoology Society, a much-needed level of scientific rigor and data are brought to a topic that is otherwise as slippery as an eel. Contrary to popular conception, the intersection between folklore and zoology is amenable to scientific analysis and has the potential to provide valuable insights into anthrozoological phenomena," says study author Floe Foxon.

On the one hand, these findings may be unwelcome for anyone consumed by the mystery of "what is Nessie?" It would have been so easy! Yet for anyone believing that the "water beast" is something much more mystical than a giant eel—as well as scientists hoping for the discovery of an altogether new species—this may, in fact, be good news. Regardless, the mystery lives on.