Sorry to say, but those are coyotes. I *wish* they were wolves. I did see wolves when I was there but they were literally a mile away and you could see them through a spotting scope, photos weren't really possible http://www.christiankiely.com/yellowstone/slides/DSCF2554_640.html
The three black bumps in the right center are 3 of the 4 wolves of the "Druid Peak" pack. That's about as close as I got... and that was w/ a 500mm lens + 2x teleconverter * 1.5 digital factor, the equivalent of a 1,500mm focal length... and they still look that small.