Within Cryptozoology
What DNA Says About the Loch Ness Monster
Loch Ness DNA surveys have weakened reptile and giant fish claims while leaving ordinary explanations such as eels more plausible.
On this page
- The classic Nessie claim
- Environmental DNA in the loch
- Why giant eel theories persist
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Introduction
The classic Nessie claim
The modern Loch Ness Monster is usually imagined as a large, long-necked creature with one or more humps showing above the water. That image became globally recognisable in the twentieth century, especially after the 1930s wave of press attention and disputed photographs. Within cryptozoology, Nessie is often treated as the archetypal “lake monster”: a claimed large animal in a bounded freshwater environment, known mainly through sightings, ambiguous images and sonar contacts rather than physical remains.
The most biologically ambitious version is the plesiosaur theory. It proposes that Nessie is, or resembles, a surviving marine reptile from the age of dinosaurs. The problem is that this theory carries a heavy burden. A plesiosaur-like animal would not be a single eternal survivor; it would require a viable population, food, reproduction, genetic continuity and opportunities to leave remains or detectable biological traces. The eDNA survey directly undermined that version because the team reported no reptilian DNA sequences in the samples. Gemmell’s public conclusion was blunt: the data gave “absolutely no evidence” for a giant scaly reptile in Loch Ness.[The Guardian]theguardian.comHis study sequenced DNA from 250 samples of Loch NessThe GuardianLoch Ness monster could be a giant eel, say scientists5 Sept 2019 — Prof Neil Gemmell, who led the ・ no evidence of plesiosau…
Other large-animal theories have also circulated: sturgeon entering from the sea, Wels catfish introduced by people, Greenland sharks or other large fish, seals, otters, swimming deer, birds, logs, waves and boat wakes. These are not all equal. Some are ordinary misidentifications; others are attempts to preserve the idea of a rare animal without invoking a prehistoric reptile. The eDNA survey made several of the large-fish explanations less attractive because the researchers reported no shark, catfish or sturgeon DNA in their sampling.[University of Otago]otago.ac.nzfirst edna study of loch ness points to something fishyUniversity of Otago5 September 2019, First eDNA Study Of Loch Ness Points To Something Fishy, News archive, Department of Anatomy | Unive…
That still leaves room for sightings to be sincere. A witness can honestly report a hump, wake, neck-like shape or moving dark mass without having seen an unknown animal. Loch Ness is long, deep, dark and visually tricky; distance, scale and water movement can make common things look unfamiliar. Operation Deepscan in 1987 illustrates the pattern: a major sonar sweep found a few unexplained deep-water contacts, but later searches did not turn them into evidence for a large animal. BBC Science Focus summarises the result as ambiguous contacts, probably debris, thermal effects or possibly a seal, with no sonar evidence that can confidently be interpreted as a giant animal.[Science Focus]sciencefocus.comScience Focus Operation Deepscan: The hunt for the Loch Ness MonsterScience FocusOperation Deepscan: The hunt for the Loch Ness Monster - BBC Science Focus Magazine…
Environmental DNA in the loch
Environmental DNA, or eDNA, is genetic material shed by living things into their surroundings. Animals leave traces through skin, mucus, scales, feathers, faeces and other biological material. In water, scientists can filter samples, extract DNA and compare sequences with reference databases to build a picture of what organisms are present. Gemmell described the method in plain terms before the Loch Ness fieldwork: life is messy, and those traces can provide a biological census of a place at a given time.[University of Otago]otago.ac.nzOpen source on otago.ac.nz.
Why giant eel theories persist
The eel theory persists because it is modest compared with the plesiosaur theory. European eels are real, present in the loch, long-bodied, capable of moving in a serpentine way, and already detected genetically. A large eel could plausibly explain some reports of a dark, elongated shape near the surface, especially if seen briefly, at distance or in poor light. Gemmell therefore treated giant eels as a remaining possibility rather than a conclusion: the data could not reveal size, and further investigation would be needed to confirm or refute the idea.[University of Otago]otago.ac.nzfirst edna study of loch ness points to something fishyUniversity of Otago5 September 2019, First eDNA Study Of Loch Ness Points To Something Fishy, News archive, Department of Anatomy | Unive…
But “more plausible than a plesiosaur” does not mean “likely to be a monster”. A 2023 JMIRx Bio paper by Floe Foxon tested the eel hypothesis statistically using available eel catch data. It found that a one-metre eel in Loch Ness was plausible, with a roughly 1 in 50,000 chance, but that the probability of much larger eels fell sharply; eels large enough to match the most dramatic monster reports were judged essentially implausible on statistical grounds.[JMIRx Bio]xbio.jmir.orgOpen source on jmir.org.
The eel theory therefore works best as a partial explanation. It may account for some long, dark, moving shapes. It does not comfortably explain very large multi-humped animals, long-necked silhouettes, or claims of creatures many metres long. Those reports still need other explanations: waves, boat wakes, birds, floating debris, photographic ambiguity, hoaxes, misremembered events or the way repeated stories train people to interpret uncertain shapes as Nessie-like.
The loch’s ecology also limits what can be proposed. A large predator needs food, and a breeding population needs more than one or two animals. A classic population-density analysis estimated the possible “monster” biomass by comparing Loch Ness with expected fish production in a deep, oligotrophic, nutrient-poor lake. Its conclusion was not that monsters existed, but that only a limited biomass of large animals could be supported, and that a viable population would have to fit within those constraints.[Harvard SEAS Courses]courses.seas.harvard.eduSEAS Courses THE POPULATION DENSITY OF MONSTERS IN LOCH NESSSEAS Courses THE POPULATION DENSITY OF MONSTERS IN LOCH NESS
This ecological point is often more damaging than any single failed search. A lake monster is not just an object to be glimpsed; it is an animal population embedded in a food web. If Nessie were a huge air-breathing reptile or giant fish species, researchers would expect more than sightings: bodies, bones, young animals, feeding evidence, repeated sonar targets, reliable photographs, tissue, or DNA. The absence of those things does not disprove every odd report, but it steadily lowers the probability that the reports are all caused by a large unknown species.
What the DNA evidence changed
The eDNA survey changed the Nessie debate by shifting it from “what could be hiding there?” to “what did a broad biological survey actually detect?” That is a stricter question. It is easy to imagine exotic animals in a deep, dark loch; it is harder to maintain those theories after a survey finds ordinary biodiversity and no genetic trace of the most popular candidates.
For cryptozoology, the lesson is not that eDNA can instantly settle every monster story. It is that modern tools can narrow the field. The Loch Ness results weakened the reptile, shark, sturgeon and catfish ideas; left ordinary eels as a real part of the loch’s biology; and made the strongest remaining explanations less spectacular. The most evidence-compatible reading is that Loch Ness contains many eels, not a confirmed giant eel monster.[University of Otago]otago.ac.nzfirst edna study of loch ness points to something fishyUniversity of Otago5 September 2019, First eDNA Study Of Loch Ness Points To Something Fishy, News archive, Department of Anatomy | Unive…
The survey also shows why negative evidence can be valuable. A failed monster hunt is not useless if it improves the map of what lives in the loch, tests specific claims and clarifies what kinds of evidence would be needed next. Gemmell argued before the results that the project was a biodiversity survey with a science-communication hook, not simply a monster chase. That framing is important: the scientific success of the work did not depend on finding Nessie.[University of Otago]otago.ac.nzOpen source on otago.ac.nz.
The popular mystery remains because sightings are human events as well as biological claims. People still watch the water, submit photographs, join searches and debate ambiguous shapes. But after the eDNA work, the most defensible lake monster theories are smaller, more ordinary and more fragmented: occasional large eels, misidentified known animals, wakes, optical effects and cultural expectation. That is less dramatic than a prehistoric survivor, but it fits the evidence better.
The evidence-based bottom line
The Loch Ness Monster has not been confirmed by DNA testing. The best-known eDNA survey found abundant eel DNA and no reported DNA evidence for a plesiosaur-like reptile, large shark, Wels catfish or sturgeon. That makes the classic Nessie claim much weaker, especially versions involving a surviving prehistoric reptile or a large unknown breeding population.[University of Otago]otago.ac.nzfirst edna study of loch ness points to something fishyUniversity of Otago5 September 2019, First eDNA Study Of Loch Ness Points To Something Fishy, News archive, Department of Anatomy | Unive…
The giant eel idea remains interesting because it is rooted in a real animal actually detected in the loch. Yet it is not a clean solution. eDNA cannot size the eels, and later statistical work suggests that modestly large eels are plausible while truly monster-sized eels are highly unlikely. The result is a narrow, evidence-aware position: some Nessie reports may have been eels, but the DNA evidence does not turn Nessie into a proven giant eel.[JMIRx Bio]xbio.jmir.orgOpen source on jmir.org.
Loch Ness therefore remains famous less because the monster claim is strong than because it is unusually testable, culturally durable and visually suggestive. In the wider cryptozoology landscape, it is a case where modern evidence has not merely failed to find the monster; it has actively pushed the best explanations towards ordinary biology and perception rather than hidden prehistoric life.
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Endnotes
1.
Source: lochnessproject.org
Title: e DN A Index
Link:https://www.lochnessproject.org/FIELDWORKGROUNDTRUTH/eDNA%20LOCH%20NESS/eDNA%20LOCHNESS_index.html
2.
Source: courses.seas.harvard.edu
Title: SEAS Courses THE POPULATION DENSITY OF MONSTERS IN LOCH NESS
Link:https://courses.seas.harvard.edu/climate/eli/Courses/EPS281r/Sources/Misc/population-density-Loch-Ness-monsters.pdf
3.
Source: lochnessproject.org
Link:https://www.lochnessproject.org/ARCHIVE%20ROOM/papershtml/LOCH_NESS_scottish_naturalist.HTM
4.
Source: otago.ac.nz
Title: first edna study of loch ness points to something fishy
Link:https://www.otago.ac.nz/news/newsroom/first-edna-study-of-loch-ness-points-to-something-fishy
5.
Source: theguardian.com
Title: His study sequenced DNA from 250 samples of Loch Ness
Link:https://www.theguardian.com/science/2019/sep/05/loch-ness-monster-could-be-a-giant-eel-say-scientists
6.
Source: sciencefocus.com
Title: Science Focus Operation Deepscan: The hunt for the Loch Ness Monster
Link:https://www.sciencefocus.com/nature/operation-deepscan-the-hunt-for-the-loch-ness-monster
7.
Source: otago.ac.nz
Link:https://www.otago.ac.nz/news/newsroom/opinion-from-otago-to-loch-ness
8.
Source: xbio.jmir.org
Link:https://xbio.jmir.org/2023/1/e49063
9.
Source: otago.ac.nz
Title: otago scientist reveals loch ness monster could be a giant eel
Link:https://www.otago.ac.nz/news/newsroom/otago-scientist-reveals-loch-ness-monster-could-be-a-giant-eel
10.
Source: Wikipedia
Link:https://en.wikipedia.org/wiki/Loch
11.
Source: Wikipedia
Title: Loch Ness Monster
Link:https://en.wikipedia.org/wiki/Loch_Ness_Monster
12.
Source: sciencefocus.com
Title: loch ness monster dna study reveals plausible explanation for sightings
Link:https://www.sciencefocus.com/news/loch-ness-monster-dna-study-reveals-plausible-explanation-for-sightings
13.
Source: sciencefocus.com
Title: loch ness monster how edna helps us discover what lurks beneath
Link:https://www.sciencefocus.com/nature/loch-ness-monster-how-edna-helps-us-discover-what-lurks-beneath
14.
Source: youtube.com
Title: Neil Gemmell
Link:https://www.youtube.com/watch?v=E4y62Pa4b28
15.
Source: thelovat.com
Title: the loch ness monster
Link:https://thelovat.com/historical-locations/the-loch-ness-monster/
16.
Source: canberra.edu.au
Link:https://www.canberra.edu.au/uc-research/institutes/iae/bulletin-board/2018/using-dna-to-unlock-the-legend-of-the-loch-ness-monster
Additional References
17.
Source: youtube.com
Link:https://www.youtube.com/watch?v=9y4SVIVPQBY
18.
Source: youtube.com
Title: Scientists Finally Explain The Loch Ness Monster
Link:https://www.youtube.com/watch?v=sKZ3dgJXIGQ
19.
Source: youtube.com
Title: The Loch Ness DNA Test Results That Terrified Scientists!
Link:https://www.youtube.com/watch?v=CcOEijIqiAM
20.
Source: researchgate.net
Link:https://www.researchgate.net/publication/390620130_The_Loch_Ness_Monster_If_It%27s_Real_Could_It_Be_an_Eel
21.
Source: researchgate.net
Link:https://www.researchgate.net/publication/392901181_Environmental_DNA_eDNA_A_review_of_ecosystem_biodiversity_detection_and_applications
22.
Source: facebook.com
Link:https://www.facebook.com/DailyHighlightmagazine/posts/after-52-years-of-dedicated-research-adrian-shinethe-worlds-leading-loch-ness-mo/900031869220154/
23.
Source: researchgate.net
Link:https://www.researchgate.net/publication/342296365_ESSAY_REVIEW_Disappointing_documentary_about_Loch_Ness_Monsters_Nessies_Can_good_documentaries_be_made_about_such_subjects
24.
Source: reddit.com
Link:https://www.reddit.com/r/Cryptozoology/comments/mrim12/loch_ness_theories/
25.
Source: facebook.com
Link:https://www.facebook.com/groups/470765477828717/posts/984205216484738/
26.
Source: facebook.com
Link:https://www.facebook.com/TessMauneNewsOn6/posts/nessie-the-eel-the-creatures-behind-repeated-sightings-of-the-fabled-loch-ness-m/2440367466000709/
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