Viral 'Loch Ness Monster' Paleontologist Tells Us What He Thinks Is Out There

During the age of dinosaurs, the oceans teemed with plesiosaurs, a family of distinctive long-necked predators that could grow to more than 80 feet in length. As charismatic sea creatures of the past, plesiosaurs have become pop culture icons, in part due to their resemblance to cryptids such as the Loch Ness Monster.

Though plesiosaurs were mostly marine animals, scientists have found tantalizing signs that some species pushed into freshwater environments, demonstrating an impressive level of adaptivity. A team has now added a new piece to this puzzle with the discovery of fossils from “​​the first freshwater plesiosaurs from Morocco,” which belonged to several adults and a baby that lived in a river system 100 million years ago, according to a recent study in the journal Cretaceous Research.

Though the research reveals important evidence of plesiosaur versatility, it was overshadowed somewhat by a reference to the Loch Ness Monster that appeared in the team’s press release, which led to scores of headlines declaring that the existence of this fabled creature is “plausible.” 

Nick Longrich, a paleontologist at the University of Bath and the senior author of the study, has some thoughts about all this. He said in an email to Motherboard that the Loch Ness Monster is certainly “fun to think about,” but added that the odds that a freshwater plesiosaur is lurking in the Scottish lake are very low.

“Is the existence of a plesiosaur in Loch Ness likely? Unfortunately, no,” Longrich said. “The existence of freshwater plesiosaurs removes one major obstacle—could a marine lineage survive in a freshwater loch? Yes! But you still have all these other obstacles to overcome.”

“Could a population of plesiosaurs survive in a lake the size of Loch Ness? Doubtful,” he continued. “It’s 22 square miles in area. The only lake with a marine mammal today is Lake Baikal, which is home to the Baikal Seal. It’s 12,000 square miles—over 500 times as big as Loch Ness. You just need a large area to hold a viable population of animals as big as a plesiosaur, and Loch Ness probably couldn’t hold more than a few plesiosaurs.”

Longrich also noted that Loch Ness is only 10,000 years old, a mere lacustrine baby compared to Lake Baikal, which is about 25 million years old. As a result of its ancient origin, Lake Baikal has “had time to evolve its own weird, endemic fish families, creating this weird lost world ecosystem that exists nowhere else,” he said. “But Loch Ness isn’t that old. 10,000 years ago, Scotland was covered by a vast ice sheet. How does Nessie survive under a glacier?”

“Last, plesiosaurs are abundant in the fossil record until 66 million years ago, and then vanish entirely,” Longrich noted. “How likely is it that they survived 66 million years and we’ve never found the fossils? Not impossible I guess, coelacanths are a living lineage that basically drop out of the fossil record after 66 million years ago. But unlikely.”

In summary, it’s interesting to entertain the idea of plesiosaurs in modern Loch Ness, but the freshwater creatures identified in the new study, which really did exist, offer a better glimpse of how sea creatures end up in unexpected habitats. 

“The transition between freshwater and marine environments, then back, is a significant evolutionary event,” said Longrich. “It’s not easy for freshwater animals to survive in very salty water, or vice versa. So it’s kind of curious to wonder why and how animals make that transition” which can so easily become an “evolutionary dead end.” 

Many animals have made the jump from saltwater to freshwater over the past several hundred millions years, including dolphins, seals, and many fish species. Animals have also returned to the oceans after living in freshwater land environments, such as the ancestors of whales. Understanding these evolutionary conversions can help scientists unravel a range of broader mysteries about life on Earth, including our own evolutionary backstory.

“It's an interesting problem because at some point we probably had to make that transition,” Longrich noted. “We drink freshwater, and maybe the evolution of land animals like humans and other mammals, dinosaurs, lizards, and so forth likely began when marine fish moved up into a freshwater habitat. We can’t be 100% confident.” 

Scientists will need to find many more fossils from bygone ages to shed light on these questions, and the Moroccan freshwater plesiosaurs add more thread to that tapestry. They are also just captivating to imagine in their own right, as inhabitants of these ancient rivers, located in what is now the Sahara, alongside a host of other predators, including the largest known carnivorous dinosaur, Spinosaurus. 

This once-lush Cretaceous scene has been whittled into fossils and stone over the ages, but it is still more real than the scintillating tales of lake monsters that have emerged from the shores of Loch Ness, along with the many other places that have reported plesiosaur cryptids (I’m partial to Ogopogo, a long-necked creature said to live in Okanagan Lake). 

“I guess the question is, why the fascination with lake monsters?” Longrich said. “I think humans are wired to be afraid of monsters—large, dangerous animals—because we grew up in Africa where there were dangerous creatures that could eat us. There were hyenas and lions in the night. And in the water, there were alligators and hippos. It was safe to assume that there were hungry animals lurking in the night, and dangerous creatures lurking in the water. And in fact it would have been dangerous to assume otherwise. So maybe there’s a part of our brain that just instinctively imagines monsters in the woods and in the waters, some survival instinct put there by evolution?”

“It's also just like… mystery,” he continued. “Science has explained the world but in the process it’s stripped away a lot of the mystery. It’s fun to think there’s still stuff we don’t know. The thing is there are things out there. I guarantee you there are new monkey species in the rainforest, strange things in the ocean. And of course the fossil record—there were plesiosaurs in a river in Africa 100 million years ago, which we didn’t even know about. And I guarantee we’ll find other things.”

“Still,” Longrich conceded, “it’s not quite the same as a lake monster.”