Hermit crab

Hermit crabs are small crustaceans that live in shells and are known to inhabit the Northern Air Temple. After outgrowing their shells, they will abandon it to find new ones.

History
These crabs were seen on the grounds of the Northern Air Temple, where Teo used them in an effort to comfort Aang, pointing out that even though the temple might have been altered by the mechanist, the creatures living there probably were direct descendants of the animals living there during the time of the Air Nomads. Brightened by the idea, Aang later compared the Earth Kingdom refugees who took residence in the abandoned settlement with these creatures by saying, that "maybe you weren't born here, but you found this empty shell and made it your home."

Anatomy
The hermit crab has two black, beady eyes and is covered in a thick coat of white hair. It has six legs, two long, curly black antennae, and a front pair of brown pincers, and it is most often found sheltering in slightly curved black and white shells.

Connection
Hermit crabs look quite similar to their real world namesake, which dwell most often in abandoned conch shells. However, real world hermit crabs do not have fur.

Behavior
Hermit crabs seem to prefer damp, dark places but are apparently quite adaptable to change.

Trivia

 * It seems fitting, and perhaps not coincidental, that an animal that is nomadic by nature would live among the Air Nomads.
 * In addition to the hermit crab, the firefly is the only other known creature to have survived since the genocide and remain in the temple.