At the Manti temple timber operation, where they were cutting wood for the temple, men would come and stay for two or three days.
After the camp had been set up for a while they would hear strange noises in the brush like a bear or something. They didn't know what it was but the dogs in camp would bark. Sometimes this thing would get close and they could see it in the edge of the fire light.
They would build a bon fire to scare it away. They would find huge tracks that it left. One night some dogs went after it nipping at it. The beast got mad and started swinging at the dogs. The other dogs joined in and circled it. The thing killed the dogs one by one. Then they heard it out with the horses. The horses were making noises in fright, but they also were silenced one by one. At this point the men were so scared they built a big bon fire and shot their guns into the dark.
Finally the beast left.
In the morning they found that the back of every horse was broken and some of the dogs had been thrown 40 feet up into trees. They figure it was the bigfoot monster.
Source: Interview with Alan Stock by Kenneth Holm, Merrill-Cazier Library, Special Collections, Folklore Collection #84, Utah State University