Appa's mother was the flying bison who gave birth to Appa and four other flying bison. She resided in the Eastern Air Temple. She was very large compared to Appa and the other baby sky bison, who were less than one tenth of her size. Even so, when Aang and Appa first met, Aang was already slightly shorter than the baby sky bison who would become his future companion.
Appa's mother appeared to Appa in a dream when he was feeling alone. She was flying along at the Eastern Air Temple, with her five calves circling around her, heading toward Sister Iio and several Air Nomad children, among whom stood Aang. She nuzzled her children tenderly, before willingly directing them to the platform where the Air Nomad boys were awaiting them. She was later one of the victims of the Air Nomad Genocide.