The wolf is an animal that inhabits the polar regions of the world and some areas of the Earth Kingdom, particularly in rural regions secluded from human settlements.
In early 100 ASC, while traveling through the woods of the northwestern Earth Kingdom, Katara, Sokka, and Bato heard the howl of a wolf. Katara commented that the animal sounded sad, to which Sokka replied that it was likely wounded. Bato informed the siblings that it had been separated from the pack, and that he understood that pain, as he endured it when the rest of the Water Tribewarriors were forced to leave him behind.[1]
Sometime after 133 ASC, in his quest for revenge against Republic City, Yakone began to teach his sons, Tarrlok and Noatak, the illegal art of bloodbending, forcing them to perform the technique on a pack of wolves. Tarrlok resented the activity when he realized that this caused the creatures pain, whereas his brother, Noatak, did not feel the same empathy. Noatak bloodbent the wolves willingly, even dragging them to the ground and forcing them to stand on their hind legs and bow.[2]
The wolf is generally a very aggressive creature, yet when manipulated through bloodbending, it will whimper in pain. These creatures are known to travel in packs, especially when searching for prey.