Ostrich horse

Ostrich horses are the main mountable animals of the Earth Kingdom, and are also frequently used as a beast of burden.

History
The animal first appeared when Iroh was captured and taken back to Ba Sing Se by a group of Earth Kingdom soldiers. After Zuko and Iroh became refugees and roamed the Earth Kingdom lands, Zuko stole an ostrich horse from Song's home, but it is unknown what happened to it after he left with Azula after the Coup of Ba Sing Se.

Anatomy
Ostrich horses are brown, bipedal, bird-like creatures approximately ten feet tall. They have two toes facing forward and one facing backward. They have wide flat tails and short, stubby wings that are most likely incapable of flight. Their heads and necks are equine, along with their tails, but their beaks and legs are avian. Ostrich horses can also jump to extremely high levels and are capable of running along vertical surfaces, even when carrying soldiers in full armor.

Connection
The ostrich horse, as its name indicates, is a cross between an ostrich and a horse. The body of the creature seems to resemble the ostrich while its tail, neck, and head resemble the horse. They also strongly resemble prehistoric "terror birds" such as the diatryma, as well as the extinct giant moa of New Zealand.

Tamed behavior


The ostrich horse is an extremely useful animal to the people of the Earth Kingdom, especially the Earth Kingdom soldiers. Bearing the name of two mountable animals, the ostrich horse is the main mount of the Earth Kingdom. Highly trained ostrich horses are even equipped with armor and used for battles by the Earth Kingdom army. Ostrich horses appear in body armor that covers their head, neck and part of their sides. These docile creatures are a lot like our version of a horse, used for transportation and to carry supplies. They can be equipped with a saddle and can be used to pull carriages and such. Ostrich horses have been known to buck and kick their riders and nearby bystanders when startled or agitated.

Trivia

 * Ostrich horses are similar to the chocobo from the Final Fantasy franchise, in terms of appearance and usefulness.
 * They may have been based on the horseclaws Kai and Kui from Nausicaä of the Valley of the Wind by Hayao Miyazaki.
 * The creatures are also similar to the hawkstriders in World of Warcraft and the bipedal horse-like animals in Ralph Bakshi's animated epic, Wizards.
 * They have a striking resemblance to the pecopeco ridden by knights or crusaders in Ragnarok.