A few Septembers ago the wife and I hiked into Cascade Lake in Yellowstone to chase grayling. We gave up on the lake and were cruising along the shoreline looking for the outlet. First, we found an area about 20x20 where the grass was all matted down. There were some pieces of elk hair and a very few pieces of bone. After doing the standard (for me) but probably dumb thing of looking closely at the carnage we went on fishing. After talking with the wolf bio about which pack probably killed the elk I sort of arrived at the conclusion that the wolves killed the elk, ate some, and then the Griz cleaned up. The next time we went to Yellowstone we carried bear spray. Never saw anything, but I suspect that "they" saw us.