With regard to the abominable snowman and bears as per the OP — One could hypothesise that the abominable snowman is a myth borne of human invention combined with the embellishment of some genuine, but highly misinterpreted, bear sightings.
This hypothesis has the benefit of:
A) Being falsifiable (by the discovery of a creature that is consistent with the legend rather than just a bear)
B) Leading to verifiable predictions (e.g. proclaimed sightings of the creature conform to observable migration patterns of bears in the region, physical evidence of the creature is analysed and found to be bear fur/droppings/whatever))
C) Being based on the wealth of evidence that human beings have a tendency to create such myths and make such embellishments
Evidentially supported, falsifiable and with potentially verifiable predictions.
Isn’t that a better hypothesis?