|Science requires solid evidence for the existence of a new species - footprints and sightings by local people are never enough. A type specimen must be obtained, which is then described in a scientific journal and continues to be available for theory experts to examine. For modern mammals this normally consists of a skin and skull that show distinctions from all similar specimens.
In his book, Dr. Krantz dissects the evidence out there, using 1965 as the starting point. Using science, his discussions center on footprints, sitings, fossil records, and of course the famous Patterson film. He looks at the difficulty in faking evidence, and explores the mythology of this creature.