A group of gemsbok bulls lived at the Ba Sing Se Zoo with various other fauna, visibly despondent over the poor living conditions that the facility provided. Aang came across the zoo during his stay in Ba Sing Se and decided to help the zookeeper, Kenji, establish a new and more expansive zoo in the Agrarian Zone. Aang used his bison whistle to lure the bulls, along with the other animals from the zoo to the Agrarian Zone, where he created new habitats for them with his earthbending.