The story, as relayed through my dad, is more or less that the man’s platoon was exchanging fire with the enemy in the jungles of Vietnam. At one point on the adjacent hill, a bigfoot-type animal walked through a clearing, went back the way it came, and then went straight up a steep embankment or cliff before disappearing into the thick jungle. The creature apparently showed no difficulty in scaling the steep incline, which impressed the man greatly.
This man told my father that he doesn’t talk about it much because he doesn’t want people to think that he’s crazy. Unfortunately, this fear is far too common among witnesses. It makes me wonder about the information that is still out there, yet remains hidden due to the fear of ridicule.
I had read of Vietnam veterans seeing bigfoot-like creatures in the jungles of Southeast Asia before, but this is as close to the source as I have ever come to one of these witnesses. Sightings from Vietnam are significant considering gigantopithecus fossils have been found there. Here is a link to an article by Russel Ciochon and Charles Yonge detailing their finds of gigantopithecus and homo erectus from the same time periods and location in Vietnam.
For those readers who are not familiar with Russel Ciochon, he is a co-author of the excellent book Other Origins, which details much of what is thought to be known about gigantopithecus. Ciochon states that he does not believe gigantos are yetis or bigfoots. But then again, why would he believe that gigantos are related to animals that he doesn’t even think are real?