Flying bison

Flying Bison, also referred to as "Sky Bison", lived in the Air Temples and were supposedly the only way to reach an Air Temple, prior to the War (other than Dragons perhaps). The most notable and possibly last surviving Flying Bison is Appa, Aang's companion and major means of long-distance transportation. A Flying Bison is first seen in "The Boy in the Iceberg". According to a behind-the-scenes interview with the show's creators, they are a hybrid between a bison and a manatee. The Flying Bison are regarded as the first Airbenders, and are highly respected by the Air Nomads.

Anatomy
Flying Bison have five stomachs, flat, beaver-like tails, brown eyes, shaggy, white fur and a brown stripe that runs along their back, from tail-tip to forehead, where it terminates in an arrowhead. They have six legs with three toes on each foot. A fully-grown Flying Bison can easily weigh ten tons. They are revered by the Air Nomads, whose tattoos deliberately emulate their arrow-shaped markings, for inspiring the Airbending art, similarly to how Badgermoles inspired Earthbending and the Dragons with Firebending.

Connection
A Flying Bison is a cross between a bison and a manatee. The real life bison shares a similar history to the flying bison, in that they were a very abundant species until foreigners came and hunted them down, reducing their numbers to near extinction. Both have also been commonly misidentified as a buffalo.

Tamed Behavior
All Flying Bison can use Airbending to fly, utilizing their broad tails to steer through air currents and also to defend themselves. As shown in "Appa's Lost Days", they are also able to use their mouths and possibly their noses to Airbend. Though fairly docile, these creatures can be fearsome when aroused to fight, as is exhibited by Appa in many cases. These creatures were the main means of transportation for Air Nomads. It was customary for young Air Nomads to choose a Flying Bison to be their lifelong companion. Aang chose Appa at the Eastern Air Temple when he was a baby, by giving him an apple. In the Northern Air Temple, Airbenders held a championship for Sky Bison Polo, as mentioned in "The Northern Air Temple". This game was played in the air; as Airbenders rode their bison, they tried to force the ball with their polo mallet into an opponent's goal. To direct his Flying Bison Appa to take flight, Aang uses the command "Yip-yip". To summon one from a far location, one may use a Sky Bison Whistle.

Trivia

 * Sky Bison are usually comfortable in the air, hence their reputation, and consequently, their name.
 * They can be presumed to be at least moderately claustrophobic, since Appa is shown to be uneasy in confined spaces, in "The Cave of Two Lovers" and "The Southern Raiders". Aang is often reluctant to lead Appa into any sort of underground cave.
 * Appa is also shown to be quite afraid of fire.


 * Once Appa dies, the species will most likely be extinct.
 * Due to the fact that the original Airbenders learned to Airbend from watching the Sky Bison, it is possible that a new race of Airbenders could be established this same way. Therefore, due to being the last of his species, Appa could potentially help start a whole new race of Airbenders. However, this seems unlikely, as Aang's son is an airbender.

Behind the Scenes

 * The movement animation of the flying bison was heavily influenced by the similarly-shaped multi-legged Catbus in Hayao Miyazaki's movie My Neighbor Totoro. The series' creators have professed their fandom of Hayao Miyazaki in many interviews.