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A review of the evidence for living plesiosaurs

by Adam Stuart Smith

A colleague and I were interviewed recently for a radio program about plesiosaurs; not surprisingly, one of the first questions posed by the host was about the Loch Ness monster. “Is the loch ness monster a plesiosaur or a cousin of the plesiosaur”? We were asked. Now the wording of the particular question surprised me somewhat - we were not asked: “do you believe that the Loch Ness monster is a plesiosaur” or even “do you believe in Nessie”. The question we were asked clearly assumes that a monster does exist in Loch Ness and that it is either a plesiosaur or a relative of plesiosaurs. Was the interviewer justified in making this assumption? In this review, I will cast a critical eye over the evidence for living plesiosaurs.

Bias?
Before I go on, it should be made clear that I have no agenda - I certainly have no reason to deny or circumvent any evidence for living plesiosaurs, indeed, I have plenty of reason to be keen on the prospect, not least because the opportunity to study a real specimen would be unmissable – the aim of my research is, after all, to understand plesiosaurs. However, this article will remain objective; it is intended to give readers a concise, unbiased, and critical review of the evidence for living plesiosaurs, from a scientific point of view, and to conclude as to the likelyhood of plesiosaurs existing today.

Photographic evidence
Even a good photograph of a clearly plesiosaur-like organism would not provide proof for the existence of living plesiosaur. It is just too easy to hoax photographs, increasingly so with the advent of photoshop etc. However, a good photograph, or preferably a good series of photographs taken in quick succession, would certainly warrant further investigation. Unfortunately, to this day, the most compelling photographs of possible living plesiosaurs have either been demonstrated or admitted as hoaxes (Fig. 1a), or are of such ambiguity or low resolution/quality, that they remain insufficient as evidence (fig 1b). All of the underwater photographs have either been reidentified at tree trunks or demonstrated to have been retouched and manipulated (http://www.museumofhoaxes.com/nessiehoaxes.html)

Video evidence
Video evidence is a step up from photographic evidence. Proponents of living plesiosaurs provide ‘the Dinsdale film’, taken in 1960, as their most compelling video evidence for a ‘monster’ in Loch Ness. For example, Bauer (2002a, p.227) states that this footage represents the “strongest objective evidence for Nessies”. The film contains a “large hump [which] moves in a curving path, submerging after a time” (Bauer 2002b p. 457). I have not seen the footage so I cannot comment in detail, suffice to say, a moving hump, is not robust evidence for a living plesiosaur.

Sightings
Sightings are less reliable than photographs. There are plenty of reported sightings of purported sea monsters, yet there are two main problems with sightings – firstly they are not testable and therefore do not provide scientific evidence. A lie detector test might determine if the witness is telling the truth or not, but this brings us onto the second problem with sightings, eye witness accounts have been demonstrated to be notoriously inaccurate. This was demonstrated at Loch Ness during the filming of the BBC documentary ‘Search for the Loch Ness monster’. A simple experiment was performed in which a stick was raised out of the water of the Loch for a few seconds and then re-submerged. A group of tourists, unaware of the experiment in progress, were asked to draw what they saw; a surprisingly large number reconstructed a ‘head’ on the end of the neck. It seems that we see what we would like to see. The human brain creates ‘models’ and interpretations of the living world that can easily fool even the most sceptical observer.

Sonar
The best sonar evidence is of too low resolution to be conclusive – and may simply represent an artefact such as water layers of different temperatures (Bauer 1988).

Anatomy
Purported living plesiosaur ‘photographs’ and ‘sightings’ often portray or describe animals that do not match the basic body shape of all known plesiosaurs. For instance, plesiosaurs do not have two humps or diamond shaped paddles, as suggested by Scott and Rines (1975) in their paper ‘naming the Loch Ness monster’. Recent studies of plesiosaur neck flexibility and posture have shown that long-necked plesiosaurs could not keep their necks out of the water as described for some sightings. Further, the necks of plesiosaurs were held-straight and rigid, they were not extremely flexible as depicted in purported 'historic art' (see below). We may predict that eyewitness accounts will ‘adapt’ to new scientific evidence.

To explain the relative lack of sightings in Loch Ness, Bauer (1988, p.14) informs us “Nessies don’t spend much time at the surface” and that “no one, including those who believe in them, should expect to see one”. But like whales, dolphins and sea turtles, plesiosaurs have lungs: they are air breathers, and so just like whales, dolphins and sea turtles, they must surface several times per day to breath. This simple anatomical fact spectacularly weakens the case for a viable population of living plesiosaurs in any lake in close proximity to human settlements etc.

Locomotion - In the ‘dinsdale film’, the “last sequence shows a definite paddling action” (Bauer 2002, p. 229). However, plesiosaurs are well known not to have paddled – they used predominantly up-down strokes, not back-forth strokes (e.g. Robinson, 1975 and others) (and see my plesiosaur locomotion page).

Carcasses
A real specimen of a living plesiosaur, or a recently deceased plesiosaur, would provide sufficient scientific evidence. Although no living specimens have been reported discovered, many corpses have been claimed to be plesiosaurs. The most famous example is the carcass of a large rotting animal which was caught in 1977 by Japanese fishermen, and claimed to be the remains of a plesiosaur. There are numerous lines of evidence discrediting this claim – most notably the fact that it is a rotting basking shark (Kuban, 1996)! Nevertheless, it is quite easy to see why an untrained eye might interpret this as a plesiosaur (Fig 2). Perhaps the most convincing piece of anatomy is what appears to be a small plesiosaur-like skull on a long neck (Fig 3). However, when compared to the chondrocranium (braincase) of a basking skark (fig 4) it is clear that the similarity with a plesiosaur is only superficial. The large jaws of the filter-feeding shark have rotted away to give the impression of a small head (the chondrocranium), and the flesh between the head and fins has rotted away to give the appearance of a longish neck.

As if to clinch the deal – DNA analysis of samples taken from this specimen have also confirmed a shark identity. The same reasoning applies to all of the other carcasses washed up on shorelines around the world. Corpses are washed up all the time, in various states of decay. It is telling that the only ones claimed to be plesiosaurs are the most decomposed ones. It is also interesting to note that no plesiosaur carcasses have ever been washed up on the banks of Lock Ness. A block of five plesiosaur vertebrae were reported from the banks of Loch Ness in 2003, but although nobody has taken responsibility, the specimen was clearly planted as a hoax or publicity stunt- the vertebrae were not recent bones, but fossilised remains, preserved in a rock type that originated many miles away from Loch Ness. (http://news.nationalgeographic.com/news/2003/07/0729_030729_lochness.html)

Historic illustrations

An illustration claimed to be recent aboriginal art depicts a plesiosaur, but it cannot be demonstrated as authentic (Fig 5). The typical medium of aboriginal art is rock - the plesiosaur art is not, plus the artwork bears striking similarity with existing modern artwork depicting plesiosaurs and is very different from authentic aboriginal artwork. The depiction is also anatomically incorrect - the necks of plesiosaurs are now known to have been held-straight and rigid, they were not extremely flexible as depicted. Even if the artwork wasgenuine, it is perfectly possible the illustration be based on fossil evidence - plesiosaur fossil remains are known from Australia.

Fig 5. Purported aboriginal art - not authenticated.

Conclusion
There is no scientific evidence supporting the existence of long necked-plesiosaurs plesiosaurs living today, and no evidence whatsoever for short necked plesiosaurs living today. There is a lack of compelling photographic evidence and a lack of demonstrable plesiosaur corpses or living specimens.

In addition, there are lines of reasoning that plesiosaurs do not exist today
The relatively low number of sightings.
The incompatibility of sightings with known plesiosaur anatomy.
The complete lack of plesiosaur fossils in recent and Cenozoic rocks.
The fact that the first sightings coincide with the first discoveries of plesiosaur.

Unfortunately, living plesiosaurs almost certainly do not exist today.

Epilogue – so why do people still believe in living-plesiosaurs?
This is an important question because while it is all well and good discrediting ‘evidence’, not all beliefs are based in evidence. There are three possible reasons for this.

The first and most widespread reason is that ‘monster fans’ want to believe in living plesiosaurs because it’s a cool prospect (it really is!). Maybe they cherry pick data, maybe they just haven’t heard the above arguments, or maybe they just don’t want to?

The second reason applies to those who have dedicated much of their time investigating ‘living plesiosaurs’ and have thus developed faith in the idea. In a personal article by Bauer, he describes his involvement searching for Nessie, and reveals a touching emotional tie with his subject matter. He claims that photographic proof was “no longer important to me”…“No such proof could add to the gifts that had already come to me through the mediation of Nessie”. While proof may not be important to Bauer, it is important to me.

The third and dangerous agenda is creationism and anti-evolution. Given that plesiosaurs are extinct and that the youngest plesiosaur specimens in the fossil record are dated at 65 million years old, it is easy to understand how a creationist might perceive the existence of living plesiosaurs as evidence against evolution and for a young earth. In reality, the discovery of living plesiosaurs would not threaten evolutionary biologists because organisms may evolve at extremely slow rates – this has already been well documented in other organisms and is termed stasis. Creationists may also believe that the discovery of living plesiosaurs would cause geologists to rethink the age of the earth, but the distribution of fossils throughout the rock record has no impact on the absolute dates of the rocks. Unfortunately, not everyone understands, wants to understand, or accepts the science behind evolution, ecological requirements for large marine predators, and how rocks are dated. For these people, the propaganda for living plesiosaurs must seem quite convincing. I hope those people find this article.

Acknowledgements
I would like to thank Phillip O’Donnell for reminding me to write this article and Henry Bauer for making much of his published work freely available online. Thanks also to Nizar Ibrahim for comments, and everyone at cryptozoology.com who commented on this article. Cheers guys!

References
Bauer, H. H. 1988. Loch Ness Odyssey, Snowy Egret, 51, 8--15
Bauer, H. H. 2002a. The case for the loch ness ‘monster’: the scientific evidence. Journal of Scientific Exploration, 16, 225-246.
Bauer, H. H. 2002b. Common knowledge about the Loch Ness Monster. Journal of Scientific Exploration, 16, 455—477.
Robinson, J, A. 1975. The locomotion of plesiosaurs. N. Jb. Geol. Paläont. Abh. 149, 286-332.
Scott P. and Rines R. 1975. Naming the Loch Ness monster. Nature 258, 466-468.
Kuban, G. J. 1997. Sea-monster or shark? An analysis of a supposed plesiosaur carcass Netted in 1977. Reports of the National Center for Science Education 17, 16-28.

Update Comments and responses

There have been a couple of responses to this article. A fundamentalist Christian with a 'young-earth' perspective, wrote a short rebuttal. I would have responded but I have already addressed all of his points. Simply put, his views are faith-based and form a nice case study for the third agenda for believing in living plesiosaurs, as outlined in the 'epilogue' section above. I will however comment on one of the figures and the caption, because I thought it was funny:

Another comment came via email from Colin G. Davis, concerning the Lie Detector Test:

"In discussing eyewitness reports of the Loch Ness Thingy, you remark that lie-detector tests might determine whether the witnesses are telling the truth. That's not a very scientific attitude! Surely lie-detectors are discredited. As I understand it, they merely record physical phenomena, and the interpretation of those phenomena is the subjective opinion of the persons administering the test.
 
Regards,
 
Colin G. Davis"

My response:

Hi Colin,
Thats an interesting point, thanks for bringing it to my attention.
I was not aware that the lie-detector test (or polygraph test) had been discredited. Although if this is the case, I would be interested in learning more about who discredited the test and when - perhaps you have a particular study in mind?
My statement agrees with the views of the American Polygraph Association -

To quote from their website:
"The American Polygraph Association has a compendium of [80] research studies available on the validity and reliability of polygraph testing" (available to purchase)

From what I gather, the results of these 80 studies ranged in accuracy from 80% to 98%, from which the Association concludes:
"that scientific evidence supports the high validity of polygraph examinations."

As you rightly point out, the tests are not infallible:
"However, a valid examination requires a combination of a properly trained examiner, a polygraph instrument that records as a minimum cardiovascular, respiratory, and electrodermal activity, and the proper administration of an accepted testing procedure and scoring system."
"the polygraph technique is highly accurate, [but] it is not infallible and errors do occur."

Although the polygraph test is not infallible, it certainly has a genuine scientific basis. Because my article states that the test "might determine if the witness is telling the truth or not", rather than "will determine", I feel that the statement agrees with the current consensus.

Thanks again for contacting me. I would like to ask permission to add your comment and my above response to my page (plus any further response you may have).
All the best,
Adam

The last word from Colin:

"Hi Adam
By all means post my remarks (as long as my address doesn't appear).
A couple of good discussions are to be found at these addresses :
http://lab.nap.edu/nap-cgi/discover.cgi?term=lie+detectors&GO.x=10&GO.y=9
http://www.usatoday.com/tech/columnist/andrewkantor/2004-04-08-kantor_x.htm
The USA Today article has a useful breakdown of the figures put forward by the Polygraph Association (who are not exactly likely to be objective, are they?).
As I said before, all the machine does is record physical symptoms, which are interpreted by the operator. I don't know about you, but I hate medical tests, and if I were stuck on a polygraph I'm sure I'd be tense and twitchy and seem like a thorough liar whatever I said.
As for the REALLY important topic - the Loch Ness monster, I'd love to believe in it (or them, as would have to be the case), but I can't. Without even considering the practical questions of food supply and sustainable population size, I'm bothered by the variety of the reports. People see so many different shapes, usually with those damned humps that seem to be essential fashion accessories for water monsters.
Another thing : I think I remember reading that during the last ice age the loch would have been frozen solid or at any rate sealed beneath ice. Doesn't that mean the creatures would have to have arrived since the ice retreated? Where from? If from the sea, would they have been able to adapt quickly to fresh water?
I'm just an old killjoy - I don't think I believe in those black panthers that keep popping up around the UK, either.
Regards,
Colin"