The Loch Ness Monster

Loch Ness, Scotland. Hundreds of eyewitnesses have reported a monster moving through these waters. Yet countless scientific studies have tried and failed to find it. I've never been diving in anything like it in my life anywhere in the world. What kind of animal could survive in these cold, dark and inhospitable waters? Now a team of eminent scientists is traveling to the loch to examine all the scientific evidence. And find out what could be living here. There is something unusual down there. The question is, what? There are few better hiding places than this remote stretch of water. For centuries, it's been home to one of the world's most enduring legends. The Loch Ness Monster. After all this time, there is little scientific evidence. All we have are hundreds of eyewitness accounts and a handful of blurred photos. But we do have a pretty good understanding of how the natural world works. And in the last century alone, we've discovered thousands of new species and even a few long thought to be extinct. So, could there be another unknown creature living in Loch Ness? I'm Philippe Cousteau and I'm here to find out. Does the monster really exist? Well, no one really knows. But as an explorer and environmentalist, I do know one thing for sure. If there really is something unusual down there, it still has to obey the laws of nature just like everything else on this planet. I'm joined by a team of experts in the fields of paleontology, oceanography and aquatic ecology. We're going to be operating from the research vessel, the MV DeepScan. We'll be using it to take samples, measurements and images from the depths below. Dr. Ken Carpenter is our dinosaur guru. He'll investigate if the monster could have survived from a prehistoric age. Maybe we should be looking more closely at the skulls of some of these prehistoric animals to see if they have any kind of adaptation for an acoustic echo sounding much like whales. Dr. Erica McPhee-Shaw knows how the dynamics of this dark, mysterious water can play tricks on the mind. It's very fjord-like, that's one thing. When I'm here, I feel like I'm in a fjord and the difference is that this is fresh water, but I'm having a hard time adjusting my mind to that. And finally, aquatic ecologist Dr. Theodore Willis will work out what kind of creatures could survive in this unique ecosystem. There isn't a lot out here to eat, so having porpoises and dolphins chase salmon upstream in the lakes like this makes perfect sense. At 22 miles long and almost 800 feet deep, Loch Ness is certainly big enough to conceal a whole community of monsters. But what kind of animal could survive in its notoriously dark and cold water? Our first step is to examine the best source of direct evidence, hundreds of eyewitness accounts. Can we see a pattern in them? In the past century alone, there have been over a thousand documented sightings of the Loch Ness monster. But as we're starting to discover, not everyone appears to have seen the same thing. Now what's interesting about this one is that she's one of the only people who sees something from really close. She says she's 20 yards away, that's a totally credible distance to make out any kind of details you want. It seems to me that the more recent sightings in the past say 20, 30 years don't have that undulating motion. As a scientist, I could not come up with one explanation that would suit all of the accounts. They're kind of all over the place, everything from nine humps to two humps to one hump to no humps to large fish. Many of the reports vary wildly, although a few common threads begin to emerge. Recent accounts talk about the creature's long neck. This feature of the Loch Ness monster can be traced back to one famous sighting. In 1933, George Spicer and his wife were driving along this road on the southern shore when they saw something they believed was a prehistoric monster. This is it. Not far from here, 1933, summer's day, the famous Spicer sighting when Mr. and Mrs. Spicer were driving in a car and they saw something cross the road. It's kind of a mystery. Well, Mr. Spicer alleges that there was some object across the road, at least one hump. There may or may not have been something in its mouth. The problem is that he saw it such a brief time, and it's very hard to judge sizes from, you know, quick whatever it was going across the road. And in the centuries and centuries that people have been living around the Loch, this is the first time that there's a description about a long neck. Yeah, it really changed what people thought of as the monster around here. This was at the time when monster movies were a huge attraction in theaters. Special effects in films like King Kong had grabbed the public's imagination. We look and laugh today, but back then it was like, that was cutting edge stuff. Yeah, so I think that whatever he saw hopping across the road, he immediately, ah, King Kong, Dinosaurus, that's it. Did the Spicers really see a long necked monster, or were they just imagining things? The following year, the single most iconic image of the Loch Ness Monster was captured on film. Here at last was evidence of Nessie's existence. Or was it? In 1993, almost 60 years later, this famous photo was revealed as a hoax. Staged by actor, filmmaker, and big game hunter, Marmaduke Weatherall. And this is how he did it. Right around here? Yeah, that looks good. More to your left. How's it look? That's really good. I'm gonna get some shots here. We said Loch Ness Monster isn't real, it's real. It seems incredible that a small model could fool the world for so long. And that's how they did it. Weatherall's photo was a phony. Yet there have been many recent sightings of a long necked monster. But our team is struggling to come up with any present day animals that could fit the bill. Especially ones that live in the water. Once you get in the water, there really isn't anything that's got a long neck. Mammals have evolved to shrink that neck. Because swimming with it isn't efficient. You've got this long rudder-like thing hanging out at the front of your body flopping all over the place while your drive system's in the back. So the fact that we haven't much around that's got that long neck really says that it just didn't work. I mean, it just, when it evolved, those things didn't make it. Long-necked marine animals have died out through the evolutionary process. And no known living creature fits the monster's description. So time to take a different approach. Next, could the Loch Ness Monster be a survivor from the age of the dinosaur? One common theory for the Loch Ness Monster is that it's a surviving long-necked prehistoric reptile, a plesiosaur. Plesiosaurs are a group of extinct marine reptiles that live during the age of dinosaurs. There are two types. There are types with a very long neck, which are elasmosaurs. And some people think that that's what the Loch Ness Monster might have looked like. The elasmosaurs are apparently forms that fed on fish based on the stomach contents that have been found, as well as their teeth. Unlike modern reptiles, which lay eggs on land, plesiosaurs gave birth in the water. This might help a Loch Ness plesiosaur to remain undetected, but it would still have to come to the surface. As reptiles, they were definitely air breathers. We see no evidence for the appearance of gills or any structures like that. They do have openings on the top of the skulls, which are clearly the nostrils. So they were definitely air breathers. These incredibly successful creatures thrived in the warm salt water of our world's oceans for more than 150 million years. But Loch Ness is a freshwater lake. Could a plesiosaur actually survive here? There are some remains that have been found up in Canada that suggest they may have ventured into rivers going up estuaries and whatnot. And it's possible that somewhere there may have been purely freshwater or lake living plesiosaurs. Could the popular image of Nessie be correct after all? Could a modern living plesiosaur survive the cold, relatively barren waters of the Loch? Well, even if it could, it would have had to survive one of the most devastating events in our planet's history. So we have to imagine about 65 million years ago, there's a huge meteorite approaching the Earth. It slowly curves its way in towards the Earth. The Earth is, you know, it's a typical day in the Mesozoic 65 million years ago. Dinosaurs are doing their thing. Plesiosaurs may have been still living in the ocean. Everybody is hunky-dory. And suddenly this huge object over 10 kilometers across comes crashing into the Earth, hits very close to the Mexican peninsula, an area called Yucatan. It sent out an incredible shockwave through the water. It probably rebounded around the Earth several times. The sheer violence of this impact threw billions of tons of vaporized rock and water into the atmosphere, blotting out the sun for months and obliterating the vast majority of life on Earth. But did this spell the end of the Plesiosaurs? Plesiosaurs, because they're air breathers, if they weren't actively breathing, would have drowned and immediately, you know, that'd been the end of them. So it was a very nasty situation to any life that was living on the Earth. And it's rather remarkable that anything survived. But we know that some animals did survive, including sharks and crocodiles. Could a species of Plesiosaur have also escaped extinction? It is quite possible that, say, a Plesiosaur that lived in the Antarctic region, opposite of the impact area, could have been sheltered from the effects of the impact. But if its ecosystem is collapsing because of the extinction of all these plankton, and then the fish go extinct, the Plesiosaur is going to starve to death. If it had found enough food to survive, could a Plesiosaur have adapted to the near-freezing conditions that exist in Loch Ness today? Evolution has done a lot of wonderful things, and it's not always predictable. Who knows what might have happened had Plesiosaurs not gone extinct? Could it be that the Plesiosaur developed a protective layer of fat, or blubber, and also evolved a method of internal heating at the same time, basically becoming warm-blooded? The interesting thing, though, is that that Plesiosaur would not have a long neck, because that would be an area of great heat loss. So Nessie, if it's really here, is probably not that long neck thing that people think they see sticking out of the water. It would, in fact, look a little bit different than what people have described. It's an attractive idea that there could be some remnant, leftover lineage that kept evolving after the dinosaurs died out, but I think it's fairly unlikely. I think people would have found some evidence, a real carcass or something, a fossil. Well, what do you know? Someone just happened to have found such a fossil, or at least they allege they did. This here is a string of four-neck vertebrae of a Plesiosaur, and it was used as evidence to prove, well, there had to have been Plesiosaurs in this area, therefore the Loch Ness Monster has to be real. Unfortunately, this type of rock appears to be a limestone, because of the way it has dissolved out. There is no limestone in this area. This rock is not native to this area. That's a clue right there to say that this fossil is a plant. It is not a natural occurrence. So it looks like the Loch Ness Monster is not a Plesiosaur. The question remains, what else could this long-necked creature be? Our investigation is about to turn up some surprising results. Our expert's biggest task is sorting out the obvious hoaxes from the scientifically plausible. Many of the sightings could have been ordinary marine life, such as large eels, Atlantic sturgeon, or even seals. At this stage, our experts are ruling nothing out. This whole reptilian idea, I keep returning to the possible concept of some sort of sea turtle. You have some that talk about multiple humps that seem to move through the water. Some of them looked like marine mammals, some of them did not look like marine mammals at all. It was used to splash water on the back of the animal. This motion sounds an awful lot like seals or walruses on a beach. There were some others that were sort of consistent of an upturned boat type shape. Single humps, no head, single hump with head, two humps with head. Some forms that describe a very long neck, describing it with having a small head. We're still left with a group of people who definitely saw something. Saw something they can't explain. Our experts next study another famous photo of the monster. This time, we know it isn't a hoax. It was taken in 1955 by Peter McNabb. Does it really show the monster? Or is it some other phenomenon, like a boat wake? How does a boat wake mimic a living creature? I think the thing about wakes is that they're a group of waves traveling, and the boat that created them might be nowhere in sight. One boat might go by and another boat might go by. Neither one of them's around. The waves can interfere. They can constructively interfere. They can cancel each other out in certain places. And you can imagine how that could really reproduce. Yeah, there you get that kind of lumpy. Yeah, the sinuous, humpy thing that's coming in and out of the water, while at the same time it's traveling. But the lock also holds a secret deep below the surface, which might explain some of the eyewitness accounts. The water in the lock often separates into two distinct warm and cold layers, divided by a boundary called a thermocline. So the thermocline itself is this boundary, which we see here in this model, representing the difference between the warm surface layer and the deep, cold water of the lake. As the prevailing southwesterly winds are funneled along the narrow, steep-sided valley, they actually push millions of tons of water downwind, forcing the thermocline down at the far end. When the winds release, the thermocline that is tilted wants to get itself back to a flat position. And you get these motions called internal waves, where the thermocline is just sloshing back and forth, like water in a bathtub, you might imagine. These giant internal waves occur hundreds of feet down, while the surface stays totally flat. But they push and pull the water the length of the lock back and forth in a massive 50-hour cycle. You would have a surface current if you went out and floated in a boat and it was perfectly still with no wind, you would move along at the speed of these currents. But now another southwesterly wind kicks in, and yet the currents underneath are flowing backwards against the wind. And it could carry something along against the wind. Could it carry like a log or some sort of debris in the water? Right. A log caught up in this cycle could easily be mistaken for a Loch Ness monster. Then there is a whole range of local wildlife that could be responsible for monster sightings. All sorts of things that live right in this region, deer, otter, grebes, swans, ducks, things that would be low in the water, definitely with a head sticking up high. And then if you have a big swan with lots of little swans behind it, at that point maybe you have a Nessie with four or five humps running behind it. Other sightings may have been down to non-native wildlife entering the lock. These could include anything from seals or Atlantic sturgeon to dolphin or maybe even whales. Again, the lock itself may have had a part to play in creating the illusion. You can get what are called inversions. It's kind of a component of a mirage. So it's essentially when you have layers of air that are different temperatures. One layer of air will actually cause the light traveling through it to bend. So an object that's way out on the horizon coming through some kind of inversion through that heated layer of air right over the water could really look a lot taller than it really is. Can flip things over so they're upside down so they look really unusual. Next, I take a plunge into the cold deep waters of Loch Ness. What kind of monster can survive this? I've never been diving in anything like it in my life anywhere in the world. Our mission to reveal the Loch Ness monster continues and we're going back out onto the water. This time we're joined by the head of the Loch Ness project, Adrian Schein. He's been at the forefront of scientific research here for over 30 years. I was an extremely unpromising school boy of the 1960s and at that time I thought that the matter of the Loch Ness monster was something that I could soon sort out and that was over 35 years ago. Today I'm taking to the water. It's my chance to experience the creature's habitat. What sort of monster could live in these cold dark waters? Is there anything to eat down there? I've dived all over the world but this extraordinary ecosystem is a first for me. If there is something unusual down there the question is what? Even through my dry suit I can immediately feel that the water is extremely cold and remember this is near the surface where the water is warmed by the sun's rays. In the depths below temperatures can be as low as just 40 degrees Fahrenheit but the worst thing is there is almost zero visibility. I can only see a few feet ahead of me and then nothing. At least I hope so. The surface team is tracking my progress through the dark and murky water using sonar. Hopefully this will also detect anything that comes too close for comfort. When they did the full lock sweep with the multi boats that there might have been some crossover that same sort of... Well it could have been although... In 1987 Adrian Shine launched one of the biggest ever searches of Loch Ness. Operation Deep Scan involved 20 boats sweeping the entire length of the lock with the most sophisticated sonar equipment available at the time. Operation Deep Scan certainly captured people's attention because it had the smell of decision about it. The idea of the inescapable curtain of sound moving from one end of the lock to the other. 20 vessels lined up across the lock and they dropped a sonar curtain I suppose you could call it. Far from solving the mystery the operation generated several strange sonar contacts that remain unexplained to this day. As for my own Loch Ness exploration there's almost nothing to see. In fact there's barely enough light to see my depth gauge or even the amount of air left in my tanks. It's time to head back to the surface. This is cool that we could see them coming up you know it gives you some confidence. Well it is very dark down there. Kind of looks like swimming in tea or maybe a little more appropriate a good good highland scotch single malt whiskey. It's got that color to it. And I tell you just a few feet underwater you really can't see anything. About 15 feet even the boat starts to pretty much disappear. It's pretty wild. I've never been diving to anything like it in my life anywhere in the world. In fact it's the perfect place for a monster to hide. Theo and Erica begin a scientific analysis of the locks near freezing water to find out what form of life could survive here. We did a Secchi disc where we dropped that white disc overboard and we measured basically the depth at which it disappears to the human eye. That gives you an estimate of what we call the photic zone how far into the lake light penetrates. And that's important because phytoplankton cannot photosynthesize where there's no light. Water samples are taken at various depths. The temperature, oxygen level, and number of plankton are also measured. All this will help to determine the size of creature the lock could support. Last thing we did was we put the tow fish over. The tow fish camera gives us a precious glimpse of the bottom almost 800 feet below. Way beyond the depth I could safely have dived. Are those biological disturbances? To see what the bottom looked like was really neat. And so even though we have this impression of the lake being very low production, you know it was neat to see the biology in there. Some of it actually is bouncing around so some of it may be plankton. My goodness you've got stuff well you've seen a lot more than I saw down there that's for sure. The tow fish reveals some of the lock's known inhabitants. Eel, trout, arctic char, and salmon. All of them feed on plankton. If we can establish the amount of plankton in the lock, ultimately we can work out if there's enough food to support a much larger predator at the top of the food chain. We took water samples and we brought them back to the laboratory to measure basic nutrients nitrates and phosphates which are necessary for photosynthesis, and we measured oxygen. So all of these give you a sense of the biological activity in the lake and what's going on there. Loch Ness is by no means a dead lake. We had daphnia, we had some different copepods, there was some small filamentous algae. Little things that are usually so small you can't see them. Tests confirm that the lock contains around 200 tons of these tiny creatures forming the bottom of the food chain. Further up this chain are the fish that we observed with our underwater camera. Is that enough food to sustain a much larger predator? So if you've got 200 tons of plankton then that can support about 20 tons of fish and then the next level is about two tons of something else, whatever that something else is. It's not a lot of organism to work with. But that's not to say that there's no food there. Just like deserts may be low productivity compared to forests but they still support a wide variety of plants and animals. While we know there's a limited food supply here in the Loch, there could just be enough to support a small number of large creatures. A much bigger problem for any potential Loch Ness monster is the cold. While the surface of the Loch never freezes, at lower depths the temperature is consistently just a few degrees above zero. How could any creature survive the intense cold of Loch Ness? We examine the evidence next. We know there is enough food in Loch Ness to sustain a large animal. The next problem is the cold. In places the water is just 40 degrees Fahrenheit, barely above freezing. Coldness is a big, big issue for me. One kind of way of possibly getting around it is what's called gigantothermy, where because of your large mass you retain the internal heat. Nature is very creative when it comes to dealing with problems. Fish, things like tuna, have developed it's not being warm-blooded but it's about as close as a cold-blooded animal can get where they actually maintain an elevated body temperature that's above the ocean around them. In mammals you find thick layers of blubber or insulation. Deep ocean is enormous and the deep ocean is colder than Loch Ness. We don't think of the deep ocean as a vast wasteland. There's plenty of life that lives in the deep ocean so I don't see the coldness of Loch Ness being a reason that no animals could exist. I certainly can't rule out the possibility that it could not have independently developed a high metabolism warm-bloodedness. Could Nessie be a warm-blooded aquatic mammal like a seal? The cold would be less of a problem if it had a thick layer of blubber. But what about the evidence? Many recent sightings are of a creature with a long neck. In the natural world, different species, as they evolve, can adopt the shape of other unrelated animals. This is called convergent evolution. So is it possible that another creature could have developed a longer neck just like the prehistoric plesiosaurs? It's not an impossibility. Certainly if we look in the fossil record we see organisms that start to have some semblance to one another. This is called convergent evolution. Convergent evolution describes the process where animals evolve very similar body forms and shapes because of the function of their body and moving around in their environment. And even though they look similar, they're not genetically related to each other at all. For example, we know that sea mammals like whales and dolphin have evolved to look like fish, despite the fact that they originally had limbs suited to walking on land. Plesiosaurs also started out with limbs and evolved to have fins and flippers so that they could propel themselves through water. With 65 million years to evolve, it's just possible that some other marine creature may have stepped up to fill the gap left by the extinct plesiosaur. In theory, an adaptation or distant relative of the sea turtle could survive in Loch Ness. Look at the requirements for living in Loch Ness. It would have to be adapted to cold. And certainly the leatherback qualifies because it has oil in its tissues which act as an insulation. It's already modified its limbs into long flipper-like structures that look somewhat like a plesiosaur. This theoretical creature has somehow gradually evolved to the size and shape of a plesiosaur. This plesio turtle could have evolved tooth-like serrations along the edge of its beak and fed on the loch's eels and salmon. Or it may have adapted its beak into fibrous, hair-like structures to allow filter feeding and survived on plankton. Either way, our theoretical plesio turtle could have adapted to live off the available food in the loch. But what about giving birth? We know that turtles lay their eggs on land, something that would give Nessie away immediately. Could our plesio turtle have evolved to give birth in the water? Certainly we know from the fossil record that this happened with some prehistoric animals where we've got the young partly coming out of the female and they both died. It's not just a single occurrence. There have been actually several of these found. So it suggests the possibility that our plesiosaur turtle might have in fact had that capacity as well of live birth. This plesio turtle meets many of the scientific requirements for a large predator living in the loch. What I've presented is actually not going to bend any evolutionary rules. It's quite possible that evolution could have produced a monster that could be adapted to living in Loch Ness. But there's another problem. How did it get here? Like any other creature living in the loch, it could only have made its home here within the last 15,000 years. Before that, Loch Ness was completely frozen by the last ice age, which began over 100,000 years ago and only ended 15,000 years ago. This whole area was buried almost a kilometer, kilometer and a half deep in just solid ice. That's an enormous amount of weight. And that ice isn't static. It's pushing slowly towards the south. And it was basically scouring out this huge valley. So anything that happened to have been living in that valley and possibly in the precursor lakes, they froze solid. If there is a creature, it had to have been introduced into the loch well after the last ice had melted away. So our plesio turtle species must have first lived in the ocean and entered the loch by the River Ness at the end of the last ice age. Fortunately, the melting ice may have made that easier. A huge flood of glacial meltwater tore through the ice dams, carving an even bigger river valley as it raced to the sea. So maybe Nessie can just swim up and down the river as she pleases. Perhaps she first ventured into the loch while chasing shoals of salmon on their way to spawn. And this migrating Nessie might well explain why she isn't seen more often. But could a relatively large creature actually make the seven-mile journey up the River Ness into the loch? If you move up from the ocean to the loch, you come over several of these places where you get these ripples, places where there are islands in the river that split things up. And at those points, it's hard to hide a large organism. Even one that's moving as fast as possible to get up in out of this into deeper water. If somebody's there, there's a good chance it's going to be seen. But there is another possibility. In the early 1800s, the Caledonian Canal was built alongside the river. Could this provide Nessie with an alternative route from the sea? If we consider the dimensions of this canal and the dimensions of these lochs, they're made for large ships and large boats to get through and into the canal. So that would definitely provide the opportunity for many types of large animals to make their way into Loch Ness. The next problem is if animals come into the lochs, why have people not seen them? Each loch seems to take about 10 minutes, and that's pretty short. But then there's like four lochs here, another couple further up, and that's a long transit. You would have to really want to not be seen and have an intent to come in when the boat's coming in and then slither along the bottom and not come up for air at all during its transit of the loch. It seems unlikely that such a large creature could make its way along the canal without being spotted. The river Ness would be a far better bet. The problem is it's shallow. In places, it's just a few feet deep. But after times of heavy rainfall, the river swells to become much deeper. So could the creature slip through at high water? You could add easily three to five feet to the depth of the river, and some places we've gone over are already six feet deep. So you're at that point of maybe 12, 15 feet. But as you add water, you add flow. When you add flow, it's more energy to get upstream. So in each case, it's a trade-off. As if that wasn't enough for Nessie to deal with, construction work in the 1800s created even more obstacles on the river Ness. At two separate points, the water is forced over man-made barriers called weirs. And this one is the closest to the loch itself. Coming from the sea, this would be the last hurdle for any creature to get through. Now, we know that migrating salmon and even large seals can make it past. But we're here to see if anything larger could make it. I'm about to find out just how tough it could be for a monster to get in and out of Loch Ness. Whatever comes up here has got to get over that weir. And finally, we examine a new theory that could solve the mystery once and for all. We've established that a candidate for the Loch Ness monster is a plesioturtle, a creature evolved from a sea turtle to resemble the size and shape of a prehistoric reptile. This Nessie gives birth to her young in the water and feeds on the loch's fish. Our theory is that the monster migrates back and forth along the river Ness to the loch. So if I can make it over this weir and into Loch Ness, then it's possible our plesioturtle could too. We're on full throttle just to keep up against the water. I think if it was like six or seven inches higher, the flow probably wouldn't be as rough coming over and we could have gotten up. I didn't think about it from out here. I was like, ah, piece of cake. When you're in there, that's pretty crazy stuff. Despite repeated attempts and several near capsizes, there just isn't enough power to make the jump. It looks like the addition of weirs 200 years ago may have closed off an open channel for Nessie. But what if a single plesioturtle was trapped in the loch by these man-made barriers? Without a mate, is there any way this species could still be alive today in the loch? Even if access to the sea is impossible, there might just be a way for our Loch Ness monster to have survived. Remember, Mother Nature is full of surprises. In 2006, at Chester Zoo in England, a female Komodo dragon named Flora astonished the scientific world when she laid a clutch of fertilized eggs despite having no contact with the male. Some of the eggs were incubated and hatched healthy offspring. This is a process called parthenogenesis. Parthenogenesis is basically what we call asexual reproduction. It's one organism making more of itself. A single female could, in fact, migrate to another island, produce a male, and then inbreed. It lets you create a family population. So instead of needing at least two of something to get somewhere, you'll need one. With our Nessie, might she be a female that's producing just one that replaces her? We don't really know. It's a possibility. Our investigation is coming to an end. Time for one last visit to Loch Ness. The idea that there could be some big animal out there that we haven't yet discovered or have never really been able to pin down, it's just an incredibly compelling one for us, for us as people. But it's awfully strange to have zero physical evidence. There's constantly discoveries of new fish species, new coral species, things that are coming up from the deep ocean that nobody knew were there. And you've had fishing boats plying the oceans with nets for centuries. If someone were to capture one, it would solve a lot. It would be exciting. I wouldn't mind getting my hands on it. It's probable the Loch Ness monster is nothing more than a combination of hoaxes and false sightings living purely in overactive imaginations. Or possibly it's just a common species, a seal, a large sturgeon, or even a giant eel. But if it does exist, then could it be a warm-blooded fish-eating plesioturtle? A member of an entirely new species trapped by man-made weirs almost 200 years ago? A monster that due to a stroke of evolutionary luck can reproduce by itself. Incredibly, this far-fetched creature obeys the laws of nature. But we didn't see any monster on our expedition and we'll never really know for sure until some hard evidence is found. So the mystery of Loch Ness lives on. And there are many other great secrets of nature still out there waiting to be found. We've only explored less than 10% of the world's oceans and lakes. And as we continue our voyages of discovery, we must take care to protect these mysterious and fragile ecosystems. In the meantime, could this be the Loch Ness monster?