Screaming or howling in Pierce County, Washington

Sound sighting only summer of 2016 on a fishing trip in Mt. Rainier National Park. A friend and I started our hike from Forest Service road 73 into Mt. Rainier Nat'l. Park via the trail that goes past Lake Eleanor. This was the closest we could get to our fishing destination, (Oliver Lake) due to longtime road closures in the area. We hiked in on maintained trails through Grand Park and down to the White River and then up Lake James. From that point it was a cross country bushwhack past Lake Ethel along Mosquito Flat onto Marjorie Lake. Our plan was for two nights at Oliver Lake but with some route finding difficulty we stayed at Marjorie lake for one night. The next morning we hiked for about fifteen minutes and located Oliver lake, set up camp and then began fishing. As we fished around part of the lake from approximately 11:00 a.m. to 5:00 p.m. I found it odd that I did not see any sign of other human evidence of any kind, ie; fisherman trails, trash, areas previously camped in, etc. By the way the fishing was fantastic all catch and release except for the last one, a nice 15 inch rainbow trout which was dinner. Later that night at in the tent my buddy and I were sharing, my buddy was fast asleep and I was tossing and turning trying to get comfortable. Suddenly I hear guttural low pitched screams coming from the ridge above us, which I estimate about three hundred feet up. Every inch of my body is at attention now and I am trying to figure out what is making the noise. The screams came in quick succession and total about 8-10 screams. By the time I wake up my buddy the screams have stopped and I explained to him what I heard. We continued to listen and did not hear anything else and eventually went to sleep. I am writing this now because it jogged my memory from watching a bigfoot show on TV last night and it really struck a chord with me and to reach out and report what I heard. I have been an active hiker, camper and fisherman for many many years and have stayed in many remote places here, Canada, Europe and South America and have never heard this type of low pitched guttural screams. I have come across bear and cougar and did not attribute this sound to any of those species. No one else in the area knew where we were going except for the park staff that gave us the permit at Carbon River Ranger Station.