Branchoria Cryptozoology Cryptozoology

Evidence-led pages on famous cryptids, real discoveries, folklore, and scientific tests.

Within Loch Ness

Why Nessie Is Unlikely to Be a Plesiosaur

A surviving plesiosaur would need a breeding population, food supply and detectable traces, not just one dramatic silhouette.

On this page

  • The breeding population problem
  • Why reptile DNA matters
  • Food, fossils and physical traces
Preview for Why Nessie Is Unlikely to Be a Plesiosaur

Introduction

The most famous version of the Loch Ness Monster is a long-necked creature resembling a plesiosaur, a marine reptile that lived alongside the dinosaurs. From a biological perspective, however, the plesiosaur hypothesis faces multiple problems at once. It is not enough to explain a single sighting or photograph. A living population would need to reproduce, find sufficient food, leave genetic traces and persist in a heavily studied freshwater lake. Modern evidence, especially environmental DNA (eDNA) surveys, has made those requirements harder to satisfy rather than easier. The result is that the plesiosaur theory is now considered one of the least biologically plausible explanations for Nessie sightings.[University of Otago]otago.ac.nzfirst edna study of loch ness points to something fishyreptile or population of Jurassic-age reptiles such as a plesiosaur present in Loch Ness. “We can't find any evidence of a creature that'…Plesiosaur Claim illustration 1

The Breeding-Population Problem

A common mistake in popular discussions is to imagine a lone prehistoric survivor. Biology does not work that way. Any large vertebrate surviving into the present would require a breeding population large enough to avoid inbreeding and extinction.

Loch Ness monster might just be a giant eel

Channel: KiniTV

Open on YouTube

Why Reptile DNA Matters

The strongest modern challenge to the plesiosaur idea comes from environmental DNA research.

Environmental DNA consists of genetic material that organisms shed into their surroundings through skin cells, mucus, waste products and other biological traces. In 2018, researchers led by geneticist Neil Gemmell sampled Loch Ness extensively and compared recovered DNA against known species databases. The survey detected thousands of organisms and successfully identified many common species living in or around the loch.[University of Otago]otago.ac.nzfirst edna study of loch ness points to something fishyreptile or population of Jurassic-age reptiles such as a plesiosaur present in Loch Ness. “We can't find any evidence of a creature that'…

What it did not find is especially important. The study found no reptile DNA consistent with a large unknown reptilian animal. Gemmell publicly stated that there was “absolutely no evidence” of reptilian genetic sequences in the samples and concluded that the plesiosaur explanation was not supported by the data.[The Guardian]theguardian.comThe GuardianLoch Ness monster could be a giant eel, say scientists5 Sept 2019 — The Loch Ness study found DNA from 3,000 species, but no…

No scientific survey can prove with absolute certainty that something does not exist. However, a large breeding population of air-breathing reptiles repeatedly using the loch should be expected to contribute detectable DNA. The fact that researchers recovered DNA from many ordinary species while failing to find evidence for a reptilian population significantly weakens the hypothesis.[Illumina]illumina.comloch ness ednaBut it did accurately identify dozens of other species: frogs, toads, ducks, all 13…Read more…Plesiosaur Claim illustration 2

The Significance of a Negative Result

Supporters sometimes argue that a rare animal could simply have been missed. In principle, that is possible for a single transient visitor. The plesiosaur theory, however, depends on a continuing population rather than a one-time occurrence.

The Loch Ness Mystery Was Just Solved — The Answer Is Not What Anyone Expected

Channel: Flash Discovery

Open on YouTube

Food, Fossils and Physical Traces

The absence of DNA is only one part of the biological case.

A population of large plesiosaur-like animals would leave other traces. Predators die, become injured, reproduce and interact with their environment. Over decades of intensive interest in Loch Ness, researchers have collected photographs, sonar contacts and eyewitness reports, but no confirmed body, skeleton, tooth, skin sample or tissue specimen attributable to a living plesiosaur has emerged.[National Geographic]nationalgeographic.comNational Geographic Scientists Are Hunting for DNA in Loch Ness—Get the FactsNational GeographicScientists Are Hunting for DNA in Loch Ness—Get the FactsMay 23, 2018 — Some cryptozoologists have argued that Nessie…Published: May 23, 2018

The fossil record creates another difficulty. Plesiosaurs are known from Mesozoic fossils and are generally regarded as having disappeared in the mass extinction event around 66 million years ago. To place living descendants in Loch Ness requires an enormous undocumented evolutionary history connecting ancient marine reptiles to a modern freshwater population. No fossil evidence currently bridges that gap.[National Geographic]nationalgeographic.comNational Geographic Scientists Are Hunting for DNA in Loch Ness—Get the FactsNational GeographicScientists Are Hunting for DNA in Loch Ness—Get the FactsMay 23, 2018 — Some cryptozoologists have argued that Nessie…Published: May 23, 2018

There is also a practical visibility issue. Plesiosaurs were air-breathing reptiles. Whatever their exact physiology, they would have needed access to the surface. A breeding population surfacing repeatedly in one of the world’s most famous and scrutinised lakes would be expected to generate clearer and more consistent evidence than the ambiguous photographs and sightings that dominate the Nessie record.[Wikipedia]WikipediaOpen source on wikipedia.org.Plesiosaur Claim illustration 3

Why the Plesiosaur Image Persists

The Loch Ness DNA Test Results That Terrified Scientists!

Channel: Did You Know?

Open on YouTube

        See on Amazon</a></div></div></article><article class="fr-book-card"><a class="fr-book-cover" href="https://www.amazon.com/s?k=Hunting+Monsters+by+Darren+Naish&amp;i=stripbooks&amp;tag=searcht-20" target="_blank" rel="sponsored noopener noreferrer" aria-label="Open Hunting Monsters on Amazon"><span class="fr-book-cover-fallback">Book</span><img class="fr-book-cover-thumb" src="https://books.google.com/books/content?id=mN2oCwAAQBAJ&amp;printsec=frontcover&amp;img=1&amp;zoom=1&amp;edge=curl&amp;source=gbs_api" alt="Cover for Hunting Monsters" loading="lazy" decoding="async" fetchpriority="low" referrerpolicy="no-referrer" onerror="this.hidden=true;this.closest('.fr-book-cover').classList.add('fr-book-cover-placeholder');"></a><div class="fr-book-info"><h4 class="fr-book-title"><a href="https://www.amazon.com/s?k=Hunting+Monsters+by+Darren+Naish&amp;i=stripbooks&amp;tag=searcht-20" target="_blank" rel="sponsored noopener noreferrer" title="Hunting Monsters">Hunting Monsters</a></h4><p class="fr-book-author">By Darren Naish</p><p class="fr-book-desc">Examines the biology behind claims of living prehistoric animals.</p><div class="fr-book-actions"><a href="https://www.amazon.com/s?k=Hunting+Monsters+by+Darren+Naish&amp;i=stripbooks&amp;tag=searcht-20" class="fr-amazon-btn" target="_blank" rel="sponsored noopener noreferrer">
        See on Amazon</a></div></div></article><article class="fr-book-card"><a class="fr-book-cover" href="https://www.amazon.com/s?k=The+Loch+Ness+Monster+by+Steuart+Campbell&amp;i=stripbooks&amp;tag=searcht-20" target="_blank" rel="sponsored noopener noreferrer" aria-label="Open The Loch Ness Monster on Amazon"><span class="fr-book-cover-fallback">Book</span><img class="fr-book-cover-thumb" src="https://books.google.com/books/content?id=eTHXAAAAMAAJ&amp;printsec=frontcover&amp;img=1&amp;zoom=1&amp;source=gbs_api" alt="Cover for The Loch Ness Monster" loading="lazy" decoding="async" fetchpriority="low" referrerpolicy="no-referrer" onerror="this.hidden=true;this.closest('.fr-book-cover').classList.add('fr-book-cover-placeholder');"></a><div class="fr-book-info"><h4 class="fr-book-title"><a href="https://www.amazon.com/s?k=The+Loch+Ness+Monster+by+Steuart+Campbell&amp;i=stripbooks&amp;tag=searcht-20" target="_blank" rel="sponsored noopener noreferrer" title="The Loch Ness Monster">The Loch Ness Monster</a></h4><p class="fr-book-author">By Steuart Campbell</p><p class="fr-book-desc">Critically evaluates plesiosaur-style interpretations.</p><div class="fr-book-actions"><a href="https://www.amazon.com/s?k=The+Loch+Ness+Monster+by+Steuart+Campbell&amp;i=stripbooks&amp;tag=searcht-20" class="fr-amazon-btn" target="_blank" rel="sponsored noopener noreferrer">
        See on Amazon</a></div></div></article><article class="fr-book-card"><a class="fr-book-cover fr-book-cover-placeholder" href="https://www.amazon.com/s?k=The+Monsters+of+Loch+Ness+by+Roy+P.+Mackal&amp;i=stripbooks&amp;tag=searcht-20" target="_blank" rel="sponsored noopener noreferrer" aria-label="Open The Monsters of Loch Ness on Amazon"><span class="fr-book-cover-fallback">Book</span></a><div class="fr-book-info"><h4 class="fr-book-title"><a href="https://www.amazon.com/s?k=The+Monsters+of+Loch+Ness+by+Roy+P.+Mackal&amp;i=stripbooks&amp;tag=searcht-20" target="_blank" rel="sponsored noopener noreferrer" title="The Monsters of Loch Ness">The Monsters of Loch Ness</a></h4><p class="fr-book-author">By Roy P. Mackal</p><p class="fr-book-desc">Covers classic monster theories including prehistoric-animal ideas.</p><div class="fr-book-actions"><a href="https://www.amazon.com/s?k=The+Monsters+of+Loch+Ness+by+Roy+P.+Mackal&amp;i=stripbooks&amp;tag=searcht-20" class="fr-amazon-btn" target="_blank" rel="sponsored noopener noreferrer">
        See on Amazon</a></div></div></article></div><div class="fr-section-footer"><div class="fr-browse-links" aria-label="Browse more on Amazon"><span class="fr-browse-links-label">Browse more on Amazon:</span><a class="fr-browse-more" href="https://www.amazon.com/s?k=Abominable+Science%21&amp;i=stripbooks&amp;tag=searcht-20" target="_blank" rel="sponsored noopener noreferrer">Abominable Science!</a><a class="fr-browse-more" href="https://www.amazon.com/s?k=Hunting+Monsters&amp;i=stripbooks&amp;tag=searcht-20" target="_blank" rel="sponsored noopener noreferrer">Hunting Monsters</a><a class="fr-browse-more" href="https://www.amazon.com/s?k=The+Loch+Ness+Monster&amp;i=stripbooks&amp;tag=searcht-20" target="_blank" rel="sponsored noopener noreferrer">The Loch Ness Monster</a></div><p class="fr-disclosure">As an Amazon Associate I earn from qualifying purchases.</p></div></div></section>

Amazon book picks

Further Reading

Books and field guides related to Why Nessie Is Unlikely to Be a Plesiosaur. Use these as the next step if you want deeper reading beyond the article.

Browse more on Amazon: Hunting Monsters Field to Lake Monsters, Sea Serpents, and Other Mystery Denizens of the Deep books The Loch Ness Monster

As an Amazon Associate I earn from qualifying purchases.

eBay marketplace picks

Marketplace Samples

Live-tested eBay searches with available results related to this page.

UsingUSA
Browse more oneBay.co.uk

Example items shown for inspiration; availability and pricing can change. Branchoria may earn a commission if you purchase through outbound eBay links.

Endnotes

1. Source: Wikipedia
Link:https://en.wikipedia.org/wiki/Plesiosaur

2. Source: illumina.com
Title: loch ness edna
Link:https://www.illumina.com/company/news-center/feature-articles/loch-ness-edna.html

<summary>Source snippet</summary><p>But it did accurately identify dozens of other species: frogs, toads, ducks, all 13…Read more…</p>

3. Source: Wikipedia
Link:https://en.wikipedia.org/wiki/Loch

<summary>Source snippet</summary><p>LochLoch is a word meaning "lake" or "sea inlet" in Scottish and Irish Gaelic, subsequently borrowed into English. In Irish contexts…</p>

4. Source: plesiosaur.com
Link:https://www.plesiosaur.com/page.php?pageID=00000000001

<summary>Source snippet</summary><p>Reptiles do not generate their internal body heat, which is why they live in warmer climates. Marine reptiles in particular need to…Re…</p>

5. Source: illumina.com
Link:https://www.illumina.com/content/illumina-marketing/amr/en_US/company/news-center/feature-articles/loch-ness-edna.html

<summary>Source snippet</summary><p>If there is a monster in Loch Ness, this geneticist will find it10 Jan 2025 — Well, the only hypothesis he could dismiss was that the mon…</p>

6. 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

<summary>Source snippet</summary><p>reptile or population of Jurassic-age reptiles such as a plesiosaur present in Loch Ness. “We can't find any evidence of a creature that'…</p>

7. Source: theguardian.com
Link:https://www.theguardian.com/science/2019/sep/05/loch-ness-monster-could-be-a-giant-eel-say-scientists

<summary>Source snippet</summary><p>The GuardianLoch Ness monster could be a giant eel, say scientists5 Sept 2019 — The Loch Ness study found DNA from 3,000 species, but no…</p>

8. Source: nationalgeographic.com
Title: National Geographic Scientists Are Hunting for DNA in Loch Ness—Get the Facts
Link:https://www.nationalgeographic.com/science/article/loch-ness-monster-scotland-environmental-dna-science

<summary>Source snippet</summary><p>National GeographicScientists Are Hunting for DNA in Loch Ness—Get the FactsMay 23, 2018 — Some cryptozoologists have argued that Nessie…</p>
Published: May 23, 2018

9. Source: nypost.com
Title: New York Post Is this the’answer’ to the Loch Ness Monster mystery?
Link:https://nypost.com/2024/12/19/science/scientists-simple-explanation-for-loch-ness-monster-mystery/

<summary>Source snippet</summary><p>Scientist reveals simple explanation for Nessie sightingsDecember 19, 2024 — Adrian Shine, a Scottish naturalist and long-time investigat…</p>
Published: December 19, 2024

10. 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

<summary>Source snippet</summary><p>Now, by seeking out monster DNA from the loch's waters, scientists think they know what's down there.Read more…</p>

11. Source: tetzoo.com
Title: sea monster sightings and the plesiosaur effect
Link:https://tetzoo.com/blog/2019/4/27/sea-monster-sightings-and-the-plesiosaur-effect

<summary>Source snippet</summary><p>plesiosaurs – can be linked to sightings of the Loch Ness Monster.Read more…</p>

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

<summary>Source snippet</summary><p>Loch Ness Monster DNA study reveals 'plausible'…Sep 5, 2019 — After combing the loch for samples of environmental DNA, they found that…</p>

13. Source: blog.education.nationalgeographic.org
Title: scientists sift for dna of the loch ness monster
Link:https://blog.education.nationalgeographic.org/2018/05/24/scientists-sift-for-dna-of-the-loch-ness-monster/

<summary>Source snippet</summary><p>Sift for DNA … of the Loch Ness Monster24 May 2018 — A new genetic study aims to find out once and for all if Scotland's most famous resi…</p>
Published: May 2018

Additional References

14. Source: reddit.com
Link:https://www.reddit.com/r/[Cryptozoology

<summary>Source snippet</summary><p>Why the Loch Ness Monster is most likely fakeEDNA is a scientific scan where scientists can gather all of the DNA of animals from a local…</p>

15. Source: youtube.com
Link:https://www.youtube.com/watch?v=vHGUbLhCyQs

<summary>Source snippet</summary><p>Loch Ness monster might just be a giant eelScotland's fabled Loch Ness monster could possibly be a giant eel scientist said on Thursday a…</p>

16. Source: researchgate.net
Title: (PDF) The Loch Ness Monster: If It’s Real, Could It Be an Eel?[16]
Link:https://www.researchgate.net/publication/390620130_The_Loch_Ness_Monster_If_It%27s_Real_Could_It_Be_an_Eel

<summary>Source snippet</summary><p>An environmental DNA (eDNA) study conducted at the loch. in 2018 detected extraordinary amounts of mitochondrial DNA. and nuclear DNA fro…</p>

17. Source: lochnessproject.org
Link:https://www.lochnessproject.org/FIELDWORKGROUNDTRUTH/eDNA%20LOCH%20NESS/eDNA%20LOCHNESS_index.html

<summary>Source snippet</summary><p>eDNA IndexNone of the loch's known vertebrate fish predators… Reptile? Prof Gemmell did lay one abiding myth to rest. There was no rep…</p>

18. Source: facebook.com
Title: What if the Loch Ness monster is more than just a myth?
Link:https://www.facebook.com/illuminainc/posts/what-if-the-loch-ness-monster-is-more-than-just-a-myth-professor-neil-gemmell-fr/1046828170821623/

<summary>Source snippet</summary><p>No evidence of a prehistoric marine reptile called a plesiosaur or a large fish such as a sturgeon were found. Catfish and suggestions th…</p>

19. Source: reddit.com
Title: so 3 years ago a new zealand scientist took some
Link:https://www.reddit.com/r/Cryptozoology/comments/14b1rzp/so_3_years_ago_a_new_zealand_scientist_took_some/

<summary>Source snippet</summary><p>E DNA…The 2018 eDNA survey at Loch Ness didn't find unknown giant eel DNA, it was merely suggested that known eel species in the Loch…</p>

20. Source: reddit.com
Title: A bit of a misconception I’ve seen going around
Link:https://www.reddit.com/r/Cryptozoology/comments/1t59ei2/a_bit_of_a_misconception_ive_seen_going_around/

<summary>Source snippet</summary><p>The 2018…The 2018 eDNA survey at Loch Ness didn't find unknown giant eel DNA, it was merely suggested that known eel species in the Lo…</p>

21. Source: reddit.com
Title: I know plesiosaurs are much bigger, but I don’t
Link:https://www.reddit.com/r/cryptids/comments/ounenk/realistically_speaking_why_couldnt_a_small/

<summary>Source snippet</summary><p>Realistically speaking, why couldn't a small population of…The Coelacanth was thought to be extinct for 66 million years until it was…</p>

22. Source: facebook.com
Link:https://www.facebook.com/TheLondonStandard/posts/tech-science-daily-believers-in-the-loch-ness-monster-have-long-thought-that-the/5846811085362504/

<summary>Source snippet</summary><p>reshwater. But they went extinct before Loch Ness was formed.Read more…</p>

23. Source: lochnessmystery.blogspot.com
Link:https://lochnessmystery.blogspot.com/2019/10/looking-back-on-edna-results.html

<summary>Source snippet</summary><p>LOCH NESS MONSTER: Looking back on the eDNA results13 Oct 2019 — No reptile DNA was found though reptiles do live by the loch such as adders…</p>

Topic Tree

Follow this branch

Parent topic

Loch Ness What DNA Says About the Loch Ness Monster

Related pages 5