Ninken

are essentially dogs that have heightened senses and abilities and as such are able to work with ninja. Although the dogs belonging to the members of the Inuzuka clan are ninken, the phrase is usually used in reference to the pack of eight ninken summoned by Kakashi Hatake. Kakashi's ninken have shown the ability to use human language, walking on water, capacity of developing combat strategies and investigative sense as well. They are supposed to be quite dangerous in combat, as Kakashi notes that they can tear their opponents apart on his command.

Kakashi summons his ninken mostly for tracking purposes. He can summon them separately, as he commonly does so with Pakkun, or all together. He can also summon them for special purposes, like he does with his Summoning: Earth Release: Tracking Fang Technique. With this technique, the dogs can travel through the ground following the scent of their target, emerging when the target is found and holding them in place. They all have a face-shaped design on their backs called, which is the sound made when all the characters in the face are put together. Appropriately enough, children use this design as the face for their scarecrows, which is Kakashi in Japanese.

In Naruto Shippūden 3: Inheritors of the Will of Fire, Ni had two ninken-like beasts at her disposal, that appear to have been mutated through the Chimera Technique.

Others

 * Giant Multi-Headed Dog (summoned by Pain's Animal Path)
 * Ni's Dogs