Discovery of freshwater plesiosaurs makes Loch Ness monster 'plausible'

For centuries, the Loch Ness monster has been the subject of folklore, sightings, and squabbles between believers and skeptics. Not to mention more than a few movies, including Nessie & Me (now streaming on Peacock!).

The first sightings date all the way back to the sixth century and they continue to this day. Of course, the most famous sighting was later determined to have been a hoax, but that hasn’t stopped true believers from holding out hope that the existence of the famed cryptid would be proven.

One particular point of contention rests on the type of animal Nessie appears to be. By all accounts, the gigantic aquatic monster of the Loch has a lot of morphological similarities to extinct plesiosaurs, giant aquatic reptiles which lived around the same time as the dinosaurs. Never mind that it would be an astounding feat of longevity for even a few individuals to have continued to thrive in the Loch while all of their contemporaries perished millions of years ago. The larger problem, at least from a biological perspective, is that plesiosaurs lived in saltwater environments and Loch Ness is freshwater.

For the most part, there’s a pretty hard line between freshwater and saltwater animals. Drop a freshwater fish in the ocean, or vice versa, and things are going to go pretty poorly for the fish most of the time. Some organisms, however, have found a way to live with one foot — or fin — in both worlds.

Salmon famously transition back and forth between fresh and saltwater environments and some porpoises have managed to swim upstream and move into freshwater rivers. It’s not unheard of but it isn’t precisely common either. Now, new research published in the journal Cretaceous Research suggests that some plesiosaurs spent considerable time in freshwater environments and might have even spent their lives there.

Paleontologists from the University of Bath, the University of Portsmouth, and Université Hassan II, uncovered scattered plesiosaur bones dating back to a 100-million-year-old river system in modern day Morocco. Among the recovered remains were those of some three-meter-long adults and a 1.5-meter juvenile. In the realm of plesiosaurs, they’re relatively small, certainly not the hulking beasts reported in Loch Ness. However, it does suggest that animals believed to be like Nessie were, in fact, capable of living in fresh water, contrary to our previous understanding.

A press release from the University of Bath says as much. “What does this mean for the Loch Ness Monster? On one level, it’s plausible. Plesiosaurs weren’t confined to the seas, they did inhabit freshwater.” The release goes on to note that the fossil record clearly shows them having died out at the end of the Cretaceous, some 66 million years go.

Even with our tongues planted firmly in our cheeks, it’s a notable discovery for the way it changes our understanding of these animals. Unlike other more modern creatures, which sometimes venture from the oceans and into rivers in search of food, the evidence uncovered in Morocco suggests these tiny plesiosaurs might have spent their entire lives in the river system. The most compelling piece of evidence are the scattered teeth the team found.

While teeth might not be the most exciting fossils in existence, they can tell us a lot about how an animal lived. In this case, the teeth are worn down in ways which are similar to Spinosaurus fossils found in the same bed. Scientists interpreted this to mean that the plesiosaurs ate the same armored fish as Spinosaurus, and those fish lived in the river system. If the plesiosaurs were merely occasional visitors who happened to die in the river, we wouldn’t expect to have seen the same level of wear.

Their discovery is proof positive that nature is much weirder than we tend to give it credit for. If an animal can make a stab at living somewhere it probably will, even if we think it shouldn’t. Maybe (big MAYBE) the same thing goes for time, and plesiosaurs are still swimming around in the loch. Keep your eyes peeled, Nessie could be out there.