The Ogopogo: Ancient Whale or Whale of a Myth?

         In Lake Okanagan, British Colombia, Canada, the most commonly sighted cryptid of the world is reported to lurk, with possibly a thousand sightings to date, about half being in the last half century. Locals say between 3-6 good sightings (although 4-5 is more usual) each year are expected. No other cryptid, while unconfirmed, has ever been seen so regularly that the people in the area can actually expect a relatively large number of decent sightings. It is also quite well documented by the Native Americans, who gave it the name n'ha-a-itk, literally "lake demon" and feared it far beyond any other creature, legendary or otherwise. It was regarded as pure evil, often attacking canoes. To appease it, Indians crossing the lake in a storm would carry some sort of small animal they could toss into the lake in case the n'ha-a-itk attacked, to distract it. This tradition was carried on by European settlers, but one famous case from around 1850 says two horses swimming behind a boat crossing the lake were pulled under, and the owner only saved himself by cutting the rope between the horses and the boat and paddling away frantically. About twenty years earlier, settlers in the Power Creek area had become so afraid of the creature they set up patrols to protect from a n'ha-a-itk attack (I use the native name for accuracy and an earlier time period; but "Ogopogo" for familiarity and the twentieth and twenty-first centuries).
         There was a rash of sightings in 1925-26, including one time where people in thirty different cars parked on an overview of the lake saw a moving serpentine shape in the water, and, when questioned, all reports described it the same, with very minor differences. A girl and her horse saw a great black serpentine creature slide off some rocks and into the water of the lake. A young lady had a similar experience. But the monster seems to have gotten friendlier, as the horse snack was one of the last attacks reported. However, most sightings after 1930 have been scattered but regular, although it seems there have been many cases of misidentification, such as with boat wakes, strange waves, and feeding fish.
        The lake is quite interesting, as it is extremely similar to Loch Ness in Scotland, the maximum recorded depths being 761 and 754 feet (lake then loch), both were formed by violent convulsions of the earth, both have rivers connecting them to the sea, both have large conifer forests on their shores, they are at almost exactly the same latitude, and both contain almost exactly the same species of fish. And to top it off, of course, probably the two most famous lake monsters dwell in these lakes. But the cryptids are quite different; while Nessie is plesiosaur-like, the Ogopogo is serpentine.
         This brings me to the description of the animal: it is described as between 15 and 80 feet long, and always dark-colored, usually black, dark green or blue, or dark brown. It does not always move; sometimes it simply lies near the surface of the water like a crocodile, perhaps basking, or moving quickly through the water. The methods of movement, however, are confusing: it has been reported to undulate horizontally, like the aforementioned crocodile, or to not twist but be propelled by unseen fins. Those who got very close to the cryptid said it had small finlike limbs that were not visible from large distances. It is classified as a "many hump" sea monster, and is probably a piscivore.
         What the animal is, assuming it exists, is, to say the least, open to debate. A new, giant species of eel? Or a more aquatically adapted large crocodilian? Maybe a primitive whale such as Basilosaurus, a 50-foot predator? Or some ancient, ancient, crocodile-like amphibian? Maybe a huge jawless fish? Or unknown aquatic snake? Perhaps just a large, slender, freshwater shark? Why not just a big, serpentine bony fish? Maybe something like a gigantic otter? Or could this all be only weird waves?
         Well, the eel and jawless fish are unlikely, as neither normally actively hunt- they are both scavengers. The otter would come up to the surface much more, although several normal river otters in a line could give the impression of humps. The snake, crocodilian, and amphibian would probably have frozen to death, being coldblooded. The bony fish possibility is simply unlikely, as no bony fish, alive or fossil, has been discovered in that shape and that size or larger. The shark is possible, but simply not probable-few true freshwater sharks are alive today, and only a very ancient few (like the six-gilled shark and frill shark) have a similar shape.
         So the proto-whale is most probable. But what are the chances a prehistoric animal would have survived all the changes of the past 34 million years without changing itself? We know Basilosaurus did not go totally extinct with no descendants; rather, it evolved, it changed, into all of our modern-day whales. The end of the Eocene epoch, when Basilosaurus died out after six million years at the top of the food chain, saw dramatic rises in temperature that caused an extinction event. No Basilosaurus could have survived, but there are examples of animals who "degenerate" or "devolve", where they evolve into many new "more advanced" species, the normal format for evolution. However, they may evolve into a genus which is extremely similar to the ancestors of that line of evolution. It is similar to convergent evolution, as the animals evolve in different time periods but a very similar environment. Maybe this could happen with something like a pod of beaked whales that had wandered into the lake, perhaps via the Colombia River.
         Well, the chances are low of anything like that happening, but let's move on to more usual explanations and the described habits: strange waves, logs, otters, etc. Of the videos and photographs I have seen, most I doubt are an actual creature. Many seem to be just waves (caused by wind) or boat wakes, and at least one I can say was just a school of bait fish (minnows, chub, small trout) close to the surface. I saw a diagram which showed several river otters in a line in the water creating an appearance of humps and a head. A famous video made by a local car salesman apparently showed a beaver on the lake. Logs are another possibility: many reports describe the "Ogopogo" as floating near the surface and then submerging. This could be caused by a decomposing log on the bottom which is propelled to the surface by a sudden release of methane, and, once the gas runs out, sinks again. Otters could again account for this. Possibly, like in Loch Ness, seals enter the lake, which would explain a lot.
         But the predatory n'ha-a-itk sounds more like a bull shark, as the serpentine shape and attacks were never connected, and bull sharks have been known to travel up rivers, especially is pursuit of salmon. The Colombia River has the world's largest sockeye salmon run every four years, so there would be plenty of food. There would also be enough prey in the lake, so a shark could either be trapped or decide to stay. Possibly the shark(s) lasted several years but got too big, and so started to attack canoes, mistaking them for larger prey. Bull sharks are notorious for human attacks in freshwater. But maybe they have died off, which would explain the cessation of attacks.
         I don't really know what to make of this, but I believe there are many cases of mistaken identity and any large animals in the lake are already known by science, just not known to be in this particular lake. So, I conclude that the Ogopogo does not exist. Please argue in the comments below!