Ever since the Loch Ness Monster was "discovered" in 1933, one popular theory has been that this lake-dwelling creature is a plesiosaur--a type of marine reptile that was supposed to have gone extinct 65 million years ago, at the end of the Cretaceous period. This is an easy claim to make, and a very difficult one to prove--and the weight of the evidence is that, if the Loch Ness Monster truly exists (and that's a very big "if"), the odds are extremely slim that it could be a plesiosaur.
First Things First - Is the Loch Ness Monster Real?
Before we get to the issue of what type of animal the Loch Ness Monster is, we first have to explore whether the Loch Ness Monster really exists. The first "sighting" of this lake dweller occurred in 1933 (perhaps not so coincidentally, the year the movie "King Kong" was released) by a local Scottish journalist who related the experience of one of his neighbors: "the nearest approach to a dragon or pre-historic animal that I have ever seen in my life," the man is quoted, and carrying what looked like an animal in its mouth.
Here, in a prehistoric nutshell, is pretty much every Loch Ness story down to the present day. Most Nessie sightings have been reported second-hand, in accounts along the lines of "Is the Loch Ness Monster real? Well, my friend's dentist's sister was walking by the lake one day when she saw..." In this respect, the Loch Ness Monster has a lot in common with other cryptic creatures like Sasquatch or Mokele-Mbembe: practically all the evidence is based on hearsay or rumor, with very little in the way of hard fact.
Of course, it doesn't help that most (if not all) of the physical evidence attesting to the Loch Ness Monster has been faked. The most famous "photograph" of Nessie was published in 1934, and conclusively identified as a fraud over 40 years later. In a 1999 book, one of the participants in the hoax admitted that this convincing-looking monster was actually a toy submarine with a sculpted head glued to one end! Another, more recent "photograph" shows only a hump in the water, which could be anything from a dead turtle to a submerged Volkswagen.
Could the Loch Ness Monster Be a Plesiosaur?
If, despite all the evidence presented above, you persist in believing in the Loch Ness Monster, you'd probably like to know what kind of animal it is. Very early on, the "Nessie-as-plesiosaur" theory was the leading contender, partly because of that faked 1934 snapshot, and partly because plesiosaurs (and other marine reptiles) were very familiar to the English and Scottish public.
However, there are a few major problems with identifying the Loch Ness Monster as a plesiosaur. Here are five of them, in no particular order:
Plesiosaurs were equipped with lungs, and needed to surface on a regular basis to breathe air. With all the eyes trained on Loch Ness over the last 80 years, you'd think this activity would have drawn some attention! As ancient as it may look, Loch Ness is only about 10,000 years old, and was frozen solid for about 20,000 years before that. The last plesiosaurs went extinct 65 million years ago, along with the dinosaurs.
Plesiosaurs (and other marine reptiles) were cold-blooded animals that needed to swim in temperate waters. The average temperature in Loch Ness is about 40 degrees Fahrenheit; it's not exactly a Caribbean paradise!
Based on its "description," Nessie would be a mid-sized plesiosaur, weighing one or two tons. There simply isn't enough food in the tiny Loch Ness ecosystem to support the needs of such an enormous beast.
There's absolutely no evidence that plesiosaurs held their necks out of the water, the way Nessie is depicted in that fake photograph. That may be the appropriate posture for a swan, but not for a fierce marine reptile that feasted on fish!
If Nessie Isn't a Plesiosaur, What Is it?
If we weigh all the available evidence about the Loch Ness Monster, the most logical conclusion is that it simply doesn't exist (of course, tourists bring in a lot of money, so it's in the interest of locals to perpetuate the myth). And even if you insist that the Loch Ness Monster is real, you can't reasonably make the case that it's a plesiosaur. What are the other options? Well, Nessie (at least when it was first sighted) could have been a seal, or it could have been an amphibian, or it could even have been an elephant. But no, it was not a living, breathing relative of Elasmosaurus.