Snake

, also known as, are the signature summons of Orochimaru, his assistant, Kabuto Yakushi, and his students: Sasuke Uchiha and Anko Mitarashi. They reside at the Ryūchi Cave.

Overview
The snakes vary greatly in size, body mass and species, from small enough to hide in one's sleeves to larger than buildings, and thin enough to be used to tie someone's hands to strong enough to choke a colossal animal like the Island Turtle. Although common snakes cannot speak human language like toads, some of their summoners could communicate with them. They are able to detect live beings by their heat and smell in order to track and lead their summoners to their prey.

Orochimaru frequently summons snakes in battle, either having them attack for him or instructing them to carry out other tasks. While most snakes are very obedient and do as they are instructed, the largest snake, Manda, demanded a sacrifice of a hundred humans in exchange for helping Orochimaru.

Snakes have also mastered the use of natural energy to enter a Sage Mode of their own. The only known way to learn it is in the Ryūchi Cave with the White Snake Sage.

Other Snakes

 * A giant brown snake was summoned in pair by Orochimaru with the aid of Kabuto to fight against Jiraiya and Tsunade.
 * A large white snake was summoned by Sasuke to defend against Deidara's explosive clay. In the manga, it was almost disintegrated as a result, but in the anime it merely suffered several burns.
 * A giant blue snake was summoned by Anko to destroy a wall in the Demon Island Laboratory.
 * Mutated two-headed snakes summoned by Ichi, which can further extend more snakes from their mouths.
 * Microscopic snakes created by Kabuto using Orochimaru's DNA. They were used to recreate Hidan and formed together into a giant black snake to drown Naruto Uzumaki.

Summoners
Orochimaru is heavily associated with snakes: his personality, appearance and even name are snake-like or orientated. After many experiments and forbidden techniques, Orochimaru's true form indeed became that of a snake. Orochimaru was also able to use senjutsu, and with this knowledge he developed the cursed seals. The first of Orochimaru's students to sign a contract with snakes, as well as the first to gain the cursed seal and survived. Anko learned several forbidden and snake-related techniques with Orochimaru, such as the Twin Snakes Mutual Death Technique. In the anime, it was also stated that she had built up an immunity to venom. Sasuke mainly used the snakes he summoned as shields to defend himself. After Orochimaru and the Cursed Seal of Heaven were removed from him during his fight with Itachi, Sasuke has not been seen summoning any snakes and has since then gained a contract with a hawk. At first, Kabuto only aided Orochimaru in summoning snakes while his arms were disabled. He later began to summon snakes on his own after implanting Orochimaru's remains into himself. Kabuto continued Orochimaru's research and discovered the Ryūchi Cave, where he learned senjutsu from the White Snake Sage. He gained access to a Sage Mode which, according to him, allowed him to figuratively transcend from a snake into a "dragon". A movie only character who used snakes mutated by the Chimera Technique.
 * Contract::Orochimaru
 * Contract::Anko Mitarashi (Incapacitated)
 * Contract::Sasuke Uchiha (Former Summoner)
 * Contract::Kabuto Yakushi
 * Contract::Ichi (Deceased)

Trivia

 * In the anime, it was mentioned by Hiruzen Sarutobi to his grandson Konohamaru that the rainbow symbolises snakes, and is deemed an omen of the coming of evil. This was recalled during the Invasion of Konoha, which was led by the snake-themed Orochimaru.
 * Snakes have long since been associated with dragons: a testament to this, after entering Sage Mode, Kabuto stated that he had evolved from being a simple snake into a dragon. Orochimaru's Eight Branches Technique is also described as ascending beyond snakes, becoming a dragon god.