Ninneko (忍猫; Literally meaning "Ninja Cat") are able to work with ninja through to their keen senses and unusual flexibility. During the series, several demonstrations felines were displayed, giving notability of similarities with a tanuki.
Most Ninneko live in a castle located in the district of heaven and do not possess affiliation with any country or shinobi villages, though a few have been shown to wear a headband with the kanji for truth or sincerity (誠, makoto) written across it, like all the hidden villages have. They protect, and roam the corridors of the Fortress and intercept any threats.
Unlike most animals, Ninneko are capable of performing techniques. Despite this they are incapable of performing Hand Seals. Ninneko have also demonstrated the ability to use Chakra Flow through their claws, making them the only animal species to use the skill.
Ninneko primarily use taijutsu due in part to their flexible muscles, which grant them great speed, and their claws which can act as a natural weapon. Nekomata has demonstrated the ability to cast genjutsu, making him the only known Ninneko able to do this.
Bakeneko (化け猫, monster cats) are large cats who have a split tail, giving the appearance of two. They are significantly larger and stronger then the average cat. How the transformation from cat to Bakeneko occurs is unknown.
- Sakura Haruno observed that a Ninneko may be defeated by throwing water over it because of its fear of getting soaked.
- ↑ Third Databook, page 129