bones and whatnot!

I was in southeastern British Columbia and had been fly fishing in a river when I noticed a small bit of whitish color peaking up from the gravel. It was buried and I had to dig it out and was surprised to find this bone. It's very, very smooth without rough edges. I don't know what it might be...

I am supposed to be looking for a man named Harry. These are three things I found in my creek and I was wanting some info. I have been a rock collector from way back but the really sent me for a loop! Hope you can help. Fun to find!~ I can see nash marks on the hip bone of whatever ate it...