well, we know more about space than we know about the depths of our oceans, which covers 70% of our planet. Even on land, there are still immense areas of land that have had little, if any, human exploration (all of northern Canada, for example). So, I don’t think it’s unlikely at all that there are things – even quite large animals – that we have not yet discovered. If any of those things correlate to any of the myths you mentioned, well who knows? I think many of those myths have some basis in reality, but that the stories are more a case of people’s imaginations running away with them. For example, in China there was a well known myth of a group of humans that lived in the trees in the mountains. Only about 40 years ago, they discovered the monkeys believed to be the basis of that myth. They really do look human though (quite large, very human looking faces, etc) – so it’s easy to see how someone could make that mistake and then that story gets repeated and embellished for a couple hundred years. VoilĂ ! A mountain tribe of tree dwellers.