Ever go to the track in Ashcroft? Rattlers ALL OVER the place around there, right up through the Thompson river valley, and on over to Vernon, Winfield, ect.
Haven't been there but used to go to Osoyoos a lot as a kid, swim, fish and do some horseback riding in the hills, lots of ratlers there. We had one shoot across the path in front of the horses, they didn't seem to like it much :-D
We have cougar tracks occasionally at the cabin, not too often, they have a pretty big territory that they cruise. See bears a bit more often but never had an issue with them either.