What is a possible reason for the cause of bigfoot?

might be evoulution because first mankind had to develop but in a certain mankind the DNA strand had a little mix and probably created big foot

There was a great man one whom took it upon himself to live on his own in the wild being nothing but his true animal and as he adapted to the wild his skin was slowly aging and his body hair grew rapidly (just like any animal) and his true name is "MickDodge"