Tony Tony Chopper/Abilities and Powers

Abilities and Powers
Though it is rare for doctors to fulfill roles other than medical practices for the benefit of those around them, as the Straw Hats' doctor, Chopper's responsibilities are not limited to medicine alone. He occassionally performs tasks like steering the ship as their unofficial helmsman. During battles, he fulfills the role of a physical fighter.

Medical Expertise
Chopper being the doctor of the crew, has a vast knowledge of medicine and medical drugs as well as the preparation of remedies and ointments from regular fruits, roots and vegetables found on most islands. Most of this was from the things he learned during his apprenticeship under Dr. Hiruluk and Dr. Kureha, with the latter teaching him most of the medicinal procedures that he has mastered. It is currently unknown how much his medical abilities have improved after the timeskip.

Devil Fruit
Chopper has eaten the Zoan-class Devil Fruit Hito Hito no Mi, which allows him to transform into a human and human-reindeer hybrid. However, the fruit has granted Chopper more than the ability to transform; it gave him human intelligence, allowing him to speak and think like a human. This is what allowed Chopper to become a doctor and learn medicine, which is impossible for a normal reindeer. Chopper usually remains in his human-reindeer hybrid, which is a tanuki-like chibi-creature. In combat, he transforms into what suits his situations the best to fight the enemy.

Rumble Ball
In addition to his three forms granted by his Devil Fruit, Chopper has invented a yellow jaw-breaker like drug called the Rumble Ball through some research. This distorts the wavelengths of the Devil Fruit's transformation, allowing him to access at least four additional transformations (or more, after the two year time skip) for three (or possibly more, after the time-skip) minutes. However, due to the unnaturalness of this alteration, the Rumble Ball's consumption must be closely monitored, and Chopper cannot take more than one every six hours. If he takes a second one, his transformation would be out of control. (The only occasion this doesn't happen is during the Davy Back Fight Arc when the Strawhats play Pirate Dodgeball. Chopper eats one Rumble Ball at the beginning of the match and one during the middle to protect Luffy.) If a third one is taken, Chopper transforms into a massive, berserk monstrosity (as witnessed at Enies Lobby and Sabaody Archipelago) with equally monstrous strength that requires lethal amounts of energy to keep active, making Chopper a danger to himself as well as others. After the time-skip Chopper only needs to take a rumble ball for one point which is revealed to be his Guard Point in Chapter 605 of the Manga. Now Chopper has full control of his Monster Point and has no reason to have to consume more then one.

Other Combative Capabilities
In addition to the transformational advantages that Chopper's Zoan forms afford him in battle, he has also been known to employ wrestling-type moves (i.e.pinning down an opponent, or smashing them to the ground by means of a supplex) from time to time. His extensive knowledge of the bipedal anatomy also proved useful when the Straw Hats were trying to bring down Oars, during which time, Chopper formulated several theories on where it was best to target the colossal adversary. And while naive, he can be quite a capable strategist, as seen on his fights against the Mr. 4 pair and Gedatsu.

Chopper, who originally was an animal, is also capable of speaking to and understanding other animals, which has come in handy during points in the story. He also has a sensitive nose that can be used for tracking.

Chopper also seems to have a technique called Tranquilizer (sometimes translated as Sedative, as is the case with the English manga), which involves Chopper injecting a substance, probably an anashetic, into the opponent making them faint. This was first used on Luffy when he had a hallucination of a tsunami about to hit them while walking to Yuba in the Alabasta Desert.

After the two-year time-skip, he is seen being able to perform formidable martial art maneuvers with his new form, Kung Fu Point, and is now able to produce a new "Horn Point" with larger "Stag Beetle" like antlers useful for digging in the ground at high speed. He also tells of how he only needs the rumble ball for one of his forms.