It used to be much more reasonable to think that there might be undiscovered large vertebrates in lakes and seas and the mountains – that is to say, monsters. Nessie. Cadborosaurus, a.k.a. Caddy. And my personal favourite, Ogopogo.
But in an age where cameras are damn near ubiquitous and something like 20 hours of video are being uploaded to YouTube every 5 minutes, if there were such monsters, I’m pretty sure that we would have something better than this by now:
This is video from Lake Champlain, which is purported to be the home of a lake monster named “Champ.” What I think is notable about this, and most similar videos, is how poor they are. This is not to say that the person who took it did a bad job, but that you have something happening at a distance so that whatever is out there can only be seen at low resolution. You’ve got a couple of indistinct shapes and some waves.
In other words, you only get the possibility of a lake monster raised when the video is crappy and ambiguous.
If there were lake monsters, it seems highly likely that by now there would be video of something that recognizable as an animal. Heck, look for the animal that has probably been the source of inspiration for sea serpent stories, the oarfish, and you can find better videos of this unusual fish that normally inhabits the deep sea:
Hat tip to Tetrapod Zoology blog.