An Animal Guide is an animal that The Avatar bonds with during their young age. Every Avatar has one, and they journey together to keep peace throughout the world. Typically, every Nation has a certain animal that has the most probable chance of becoming an Animal Guide. For example, the Air Nomads have the Sky Bisons, the Fire Nation has the Dragon, and the Water Tribe has the Polar Bear Dog. It is unknown what the Earth Kingdom's typical Animal Guide is, as Avatar Kyoshi was never seen with her Animal Guide.
While the Avatar is a child, they meet an animal that becomes their lifelong companion. This is what is called their Animal Guide. It happens to Avatar Aang when he and the rest of the Air Nomad children are allowed to pick a pet to play with and be with forever. Without thinking, Aang gives a Sky Bison, Appa, an apple. This is what created the bond between them, which has grown since. A similar process occurs with each Avatar. However, it is unknown if they always choose their animal ritualistically, or if it happens normally in every Nation other than the Air Nomads. The only original bonding and meeting that was shown during Avatar: The Last Airbender was the sharing of the apple between Appa and Aang.
After the Avatar learns that they are indeed the Avatar, the Animal Guide and the Avatar usually develop a much deeper bond, taking over even what they had before. This is because most of the Avatars go on a journey to save the world from some evil (for example, Aang had to defeat Fire Lord Ozai and the Fire Nation to save the world), and they always have their Animal Guide with them to assist them on their travels. Using the Animal Guide, they often can get out of tight spots against the great evil that they are warring against. All Animal Guides have an instinctive nature that allows them to hurry out of tight spots, and all of them are great listeners to the people that they develop a bond with.
 Spirit World
- Main Article: Spirit World
When the Avatar passes on to the Spirit World and is reincarnated, they take their Animal Guide with them. The Animal Guide remains as the guide to the Avatar Spirit instead of just their specific Avatar. For example, Avatar Roku sent out his Animal Guide, a Dragon named Fang, to tell Aang to travel to the Crescent Island in the Fire Nation during the Winter Solstice so that he would be able to speak to him and inform him of the great danger currently happening in the war.
 Known Animal Guides