Zoan (動物系 [ゾオン], Dōbutsukei [Zōn], literally translated as Animal System) is a type of Devil Fruit. This type of fruit allows the user to transform into an animal and animal-human hybrid forms at will. Zoan types are especially effective in close combat.
1.1 Inanimate Object Zoan
4.1 Carnivorous Zoan
4.2 Ancient Zoan
4.3 Awakened Zoan
4.4 Mythical Zoan
5 Other Information
6 List of Known Zoan Fruits
A Zoan fruit allows the user to transform into one other species. This type of fruit provides three forms: the user's natural form, a fully transformed type, and a hybrid form, combining both original and fruit-bestowed species into an odd form (usually in a bizarre way where the size is greatly exaggerated). The only known hybrid forms of human users shown so far that was not bipedal is the Hebi Hebi no Mi series (as snakes don't have legs). Another effect shown is that in many different known zoan users, when in a half-human half-animal hybrid, sometimes the user tends to get bigger than they originally are, even to giant proportions. Lately, it has been seen that some Zoan users can transform partially into his animal form: Marco transformed only his arms into phoenix's wings and Onigumo only sprouted spider arms and abdomen, those two maintaining his human form and appereance.
It is unknown what happens in most cases of eating a fruit bestowing the powers of the same species who ate it, but it was stated in in the SBS that a human who eats the Hito Hito no Mi would become "enlightened".
Inanimate Object Zoan
Inanimate objects have been shown to be able to "eat" Devil Fruits. So far only Zoan type inanimate objects have been shown. Objects that eat a Zoan Fruit gain the mobility and intelligence of the animal they turn into. This can be a drawback as the object can also feel pain as being susceptible to diseases. In the animal form, they can be intimidated, as seen when Franky threatened Funkfreed. The technique used to make objects "eat" a fruit was developed by Professor Vegapunk. This has only been used on weapons so far, to increase their destructive power. Inanimate object Zoans also seem to be very loyal to whoever owns them.
The Zoan fruits mainly improves physical abilities and allows the user to use his or her three forms to adapt to a situation during a fight to find the form that gives the biggest advantage.
Zoan powers are usually utilized for their hybrid form, as this form usually (seen thus far) enhances the physical statistics of the user by combining positive attributes from both the user and the physical-level equivalent of the Zoan species. Having this advantage being based on the user's strength, though minimal on normal humans, proves to be an excellent physical enhancement for people of superhuman levels. Zoan fruits are thus favored among already superhuman users who prefer to enhance their physical abilities for the use of martial arts. This as well as creating new fighting styles, most noticeably Onigumo's Hachitōryū thanks to his six spider arms.
In their hybrid form, Zoan users experience enhanced senses, as this form uses a combination of both user and fruit abilities. Skilled Zoan users are also capable of using their powers to shape-shift out of harm's way; this is particularly useful, especially when the Zoan's body has been restrained, as Chopper demonstrated so many times (such as Chopper switching from heavy point to the smaller brain point to dodge a strike).
This type can be applied to weapons and other objects, giving life to that which is lifeless.
This fruit type is also useful for applying to objects such as guns or swords, giving an otherwise inanimate object life and increasing its value to the owner of the item. The method of application is however, as of yet, unknown.
Zoan could be considered amongst the least impressive type of Devil Fruits, as they primarily rely on brute force and some are very weak (e.g. the Inu Inu no Mi Dachshund model). However, rare Zoans such as those labeled "Mythical" or "Ancient" may display some attributes of Paramecia and/or Logia classes to generate rare and incredible powers combined in one person; the phoenix's rare ability to instantly regenerate from any wound makes it virtually equivalent to Logia users in damage tolerance.
Physical powers granted are limited to just the capabilities of the proportionate physical equivalent of the animal they are able to transform into. In hybrid form, these strengths of both species may be combined, but again seems to be just a mixture of both forms.
Furthermore, inanimate objects animated to life through the use of Zoan fruits become living creatures that need to be fed and groomed. Also, these once-inanimate objects gain their own free will and basic life's weaknesses, such as Funkfreed being threatened by Franky and Lassou contracting a cold.
Among the Zoan Devil Fruits and users, some of them can be categorized together into common types with common traits depending on what type of animal they turn into.
As stated by Tony Tony Chopper, animals of the Carnivorous Zoan (肉食の動物系, Nikushoku no Zōn-kei) are more predatory and bloodthirsty than others by nature and as carnivorous species tend to be better adapted for combat. Users that turn into such animals are naturally more dangerous and powerful in physical combat, and may have useful features such as claws to aid in a fight. One of the most extreme examples of such a Zoan user is Rob Lucci, who went as far as to maul his opponent in full-leopard form.
As stated by Scratchmen Apoo, the Ancient Zoan (「動物系」古代種, Zōn-kei Kodaishu) is apparently a much rarer type of Zoan Devil Fruit which allows the users to transform into ancient and extinct animals, such as prehistoric reptiles like the dinosaurs. The only Ancient Zoan that has been shown so far is wielded by X. Drake, allowing him to transform into a carnivorous dinosaur.
As explained by Crocodile, the Awakened Zoan (覚醒した「動物系」, Kakusei Shita Zōn-kei) are users who have by unknown means attained the ability to be stronger, faster and tougher than what the Zoan Devil Fruits' abilities bestow normally. This also includes faster recovery time, which functions involuntarily even when the user is unconscious. So far, all awakened Zoan fruit users have shown no signs of complex thoughts, seeming to act out on instinct and power. They are always in an animal form and yet they are somehow able to stand erect and to hold weapons. The four Demon Guards are all classified as such users.
Mythical Zoan (「動物系」幻獣種, Zōn-kei Genjūshu) fruits are an exceptionally rare type of Zoan Devil Fruit and is said to be even rarer than Logia Devil Fruits. They allow users to transform into mythological creatures (which may have special abilities that are comparable to Paramecia and Logia Devil Fruits), the sorts of which could be regarded as the subject of legends and the like. The only one shown so far belongs to Whitebeard's 1st division captain, Marco the Phoenix.
While most Zoan users can only use the three forms, the Straw Hat Pirate's doctor Tony Tony Chopper can utilize more forms for a given amount of time with the aid of the "Rumble Ball", which he developed. It's unknown if other Zoan users can also be affected by the Rumble Ball since so far only Chopper has eaten it. However, consecutively eating two or three under six hours can cause disastrous results, as the tampering with a Devil Fruit's powers is not something meant to be done.
Another research done on the Zoan-class Devil Fruit, by Dr. Vegapunk, is to apply the fruit into an inanimate object. This gives the said object new life, and is usually administrated into weapons, creating mobile weapons with their own minds. Only Lassou, Funkfreed, and a flail used by a Whitebeard Pirates' commander have been seen going through this phenomenon.
A majority of the Zoan Devil fruits also come in different "models" that result in variations of the animal. For example, the Inu Inu (Dog) Fruit has Jackal, Dachshund, and Wolf models, the Ushi Ushi (Bull or Cow) Fruit has Bison and Giraffe models, and the Hebi Hebi (snake) has Anaconda and King Cobra models.
List of Known Zoan Fruits :
Inu Inu no Mi (Dog) series:
Inu Inu no Mi, Model: Jackal (English versions: Mutt-Mutt Fruit: Jackal Strike/Dog-Dog Fruit: Model Jackal/Mutt-Mutt Fruit: Jackal Mode)
Inu Inu no Mi, Model: Dachshund (English versions: Mutt-Mutt Fruit/Mutt-Mutt Fruit, Dachshund Type/ Mutt-Mutt Fruit, Dachshund Variety)
Inu Inu no Mi, Model: Wolf (English versions: Mutt-Mutt Fruit Wolf Model)
Ushi Ushi no Mi (Cow) series:
Ushi Ushi no Mi, Model: Bison (English versions: Ox-Ox Fruit/Ox-Ox Fruit, Bison Model/Ox-Ox Fruit, Bison Form)
Ushi Ushi no Mi, Model: Giraffe (English versions: Ox-Ox Fruit, Giraffe Model)
Neko Neko no Mi (Cat) series:
Neko Neko no Mi, Model: Leopard (English versions: Cat-Cat Fruit: Model Leopard)
Tori Tori no Mi (Bird) series:
Tori Tori no Mi, Model: Falcon (English versions: Tweet-Tweet Fruit/Tweet-Tweet Fruit, Falcon Type/Bird-Bird Fruit, Model: The Falcon)
Hebi Hebi no Mi (Snake) series:
Hebi Hebi no Mi, Model: Anaconda (English versions: Snake-Snake Fruit: Model Anaconda)
Hebi Hebi no Mi, Model: King Cobra (English versions: Snake-Snake Fruit: Model King Cobra)
Single model series:
Hito Hito no Mi (English versions: Human-Human Fruit)
Mogu Mogu no Mi (English versions: Diggy-Diggy Fruit/Mole-Mole Fruit)
Uma Uma no Mi (English versions: Horse-Horse Fruit)
Zou Zou no Mi (English versions: Elephant-Elephant Fruit)
From : http://onepiece.wikia.com/wiki/Zoan/