Report 1530: Fly Fisherman sees a hairy bipedal creature while trout fishing

I had hiked downstream on the Missouri River from Hauser Dam for an evening of flyfishing for rainbow trout. This was during August, 1977. As usual, I kept fishing until well after dark. About 11:00 p.m., there was no moonlight and it was so dark I could only see a few feet in front of me. I had a large flashlight/lamp with me which I laid on a large boulder with my flybox. Just below the boulder, I placed some rocks in a circle near the river's edge to put my trout so they would keep fresh. I was fishing about 20 yards upstream of the boulder that held my lamp when I suddenly realized that I had lost my fly. I proceeded back towards the boulder to put on another fly. As I approached the boulder I could see some kind of movement but it was too dark to make out what it was. When I reached the boulder, I switched on my lamp with the beam pointing above the boulder towards some brush up the steep embankment. I was startled to hear a crackling sound and see movement from the brush. I pointed the beam directly at the movement only 10 feet from me and got a full view of a hairy bipedal creature moving very rapidly up the bank and quartering away from me in the downstream direction. It was very large and muscular with long dark hair and seemingly no neck. Estimated height is about 7-8 feet, guessing 400-500 pounds. I could not see its face as it was moving away from me. It took long, powerful strides and its arms moved powerfully as a man would walking very rapidly. It was amazing to see how quickly it traversed over the boulders and up the steep embankment. I had the creature in the lamp beam for only a few seconds before it disappeared into the darkness. I was stunned at what I had just seen and tried to rationalize what it could have been. For some strange reason, I felt absolutely no fear. The sense I had was that this was an animal of some sort that was frightened away by my light and posed no threat to me. However, that changed somewhat when I shined the lamp towards the rock pool where I had been keeping my trout. Before the sighting of the creature, I had four trout ranging from 2 to 3 pounds in the pool. After the sighting, there were only two trout. This explained the movement I detected as I was approaching the boulder. The creature must have been innocently foraging along the river's edge and found an easy meal. What caused me some concern was that the creature might come back and fight for the remaining two fish. Then I heard a boulder crashing down the hillside, probably several hundred yards down the river. I therefore felt some comfort that the creature was still running away from me. At that point, I picked up the two remaining trout and hiked back up to Hauser Dam and crossed the river to my vehicle and went home. I have only told this story to my wife, a couple of close friends and to a bonafide researcher in Helena.