In an increasingly bland, sanitised world, I would like to believe in these crypto zoological 'mythical' beasts, however, I have serious doubts.

I suspect these creatures which inhabit the shadows are a product of the way the human brain and the senses, interprets and collects information. I do not doubt people, even experienced country people, have not spooked themselves with shadows in their peripheral vision. However, the solution lies in neuroscience.

Animals work on fight or flight and the rapid collection and analysis of data. Split second decision, based upon incomplete data can have survival consequences. The brain tries to make sense of the data - like a jigsaw missing several pieces and fills in the missing bits itself - "run" or "fight" because there is a partially concealed / obscure threat stalking up on you. Magicians make use of the way people take in information too.

For a yeti type animal to exist, it needs food, water and shelter. It needs a wilderness area without significant human encroachment. It also needs certain numbers within these wilderness areas to maintain a breeding population. So putting the aspects together, there should be more, unambiguous sightings, tracks and signs. Ok cats bury their scat but they leave paw prints and hair rubbed off against obstructions. Also, dead bodies would turn up occasionally. With the indigenous Americans and the Mountain Men, I would have thought a skin / body / bones would have turned up by now.

There is a closed foot tunnel beneath the River Thames in London. It is now used as an electric cable tunnel etc. Maintenance people visit not infrequently and it is 'spooky'. Story is it is haunted - the bad feeling, a 'presence' experienced by technicians working in the tunnel. It turned out, people were subconsciously picking up very low frequency, background 'earth noises' and vibrations. the human brain, in an attempt to make sense of these stimuli provided it's 'interpretation.