The hog monkey is a primate that inhabits the Earth Kingdom. It is considered difficult to tame and does not take well to being ridden, though it can usually be coerced into doing so with lychee nuts.
While walking through the forest near Gaipan, Aang, Sokka, and Katara came across a pair of hog monkeys that were caught in Fire Nation traps, having been tempted by a pile of lychee nuts; they were subsequently freed using Sokka's boomerang.
A group of hog monkeys were among the species that lived at the Ba Sing Se Zoo, though their cage was unclean and dark and the animals themselves were unhappy. Aang came across the zoo during his stay in Ba Sing Se, and seeing the poor conditions, endeavored to release the animals from their cages and move them to a more expansive zoo in the Agrarian Zone. However, after being released, the hog monkeys began harassing the citizens of the city and destroying a number of shops. Upon hearing the signal from Aang's bison whistle, the hog monkeys ceased their destruction and rushed with the other animals to follow the sound, eventually finding themselves in the much larger zoo Aang had created outside the city walls.
The hog monkey has a vaguely canine face, a long tail, and the body of a primate. It appears to run on its knuckles and has a long tail. In addition, the hog monkey has reddish eyes and a dog-like snout that is full of sharp teeth, including two tusks protruding from the lower jaw. Its fur is brown on most of its body, although the area around its face and head is of a much darker shade.
The hog monkey commonly roams in troops or small packs. Although it does not really resemble a hog in any way, its noises are swine-like in nature. The hog monkey tends to be a troublesome animal if it is let loose in the city. According to Aang, a wild hog monkey does not enjoy being ridden, but its resistance can make riding it enjoyable.
The hog monkey is a cross between a hog and a monkey.
- The leader of the Zhang tribe wore a shirt made out of hog monkey hide.
- One of the Avatar relics is a wooden hog monkey toy.
- The evening after the Freedom Fighters fought a group of Fire Nation soldiers, Jet recalled The Duke's fighting, describing how he rode one man "like a wild hog monkey."
- Sokka once pretended to be a hog monkey during an exercise for Earth King Kuei's pet bear, Bosco; while trying to return Bosco to using his natural instincts, Sokka impersonated the animal and acted as though he were trying to steal Bosco's food, but his plan did not execute as he had hoped.
- The fisherman used the phrase "Well, I'll be a hog monkey's uncle" after realizing Aang was the Avatar. This is a play on the real-world expression, "Well, I'll be a monkey's uncle."
- Aang mentions hog monkeys briefly in the unaired pilot, asking Momo whether he would save him from a pack of wild hog monkeys, in an attempt to justify his desire to save Sokka and Kya from the Fire Nation.
- In the Avatar: The Last Airbender video game, hog monkeys roam in troops around a small fishing settlement and are blamed for the disappearance of food from the village.
- After the Hundred Year War, a pro-bending team named itself the Harbor Town Hog Monkeys.