The yak who runs Zootopia’s naturalist club is Yax.
Yax is a laid-back domestic yak who operates the Mystic Springs Oasis club in Sahara Square. The club is a naturist venue, meaning its members do not wear clothing there. Judy Hopps and Nick Wilde visit it while following the trail of Emmitt Otterton, because Otterton had recently been seen at the club.
Yax’s relaxed personality and philosophical, unhurried speech make him one of the film’s comic supporting characters. He initially seems distracted, but he provides an important clue: Otterton was behaving strangely before he disappeared. That information helps Judy and Nick connect the missing predators to the larger mystery.
The question sometimes causes confusion because Yax is identified by both species and occupation. He is not simply a generic yak in the background; he is the named owner and host of the club. Tommy Chong provides Yax’s voice in the 2016 film.