Either those wolves truly saw him as prey, or he was being ultra sneaky going through the woods. I have come up on wolves grouse hunting in very thick cover, not being particularly quiet, but have only seen them when wind was in my favor. Even in those instances I think they just wait to see what you are before slinking off, and I've only caught a glimpse of them. Pretty much impossible to "sneak up" or stumble upon 3 wolves. Too many of those things in the great lakes region, and fear of humans is being lost. I love having them around, but just like any other predator, they need to be managed.