The encunter wolf, also known as a "Wild Wolf" or WW, has a low chance of you catching it. Theres no strategy, just pure luck! Don't fret, they're shy sometimes :> (Send me a message if you need further explination!)
I feel that their encounter rates are also pretty random. Sometimes I can spend hours in Campaign and not encounter a single WW but then on other days I can find two or three back to back.
Another good thing about encountering them though is, even if you don't befriend them and take them home, they will give you a Knucklebone. Once you collect 50 of these it will unlock a hunt that, if completed, is a guaranteed WW.
But, don't get too discouraged with the encounter rates for the ones in Campaign. Eventually, you'll get one. I've been playing for almost two years now and I still get excited when one comes home with me. xD
Yeah, the RNG is just crazy sometimes. Like, I hadn't found any for . . . I don't know how long, and then yesterday I got, like . . . three? Just be persistent! It pays off eventually, and even if you get a WW you don't like you can usually sell them for a decent amount in the Flea Market!