|Photo Credit by SergiART|
A running gag is that various characters in One Piece think Chopper is a tanuki (raccoon-dog, often simply translated as "a raccoon") while in his Brain Point or hybrid form. The word "tonakai", which is the Japanese word for "reindeer", is where the "Tony" in Chopper's name is derived from. His Heavy Point or human form is likewise mistaken for a gorilla (or an abominable snowman on his home island).
Before the Timeskip
Similar to most of his male crewmates, Chopper has the same outfit throughout most of the series.
In the Alabasta Arc, he wore a shirt with a green-lined collar, then a bigger one with giant sleeves that is light blue with dark blue liners.
In the Enies Lobby Arc, he wore a red leather jacket.
After the Timeskip
After two years, Chopper is significantly leaner. He is less potbellied than he was in earlier seasons and his arms/forelimbs are also skinnier. It is arguable that since leaving the cold climate on Drum Island, he has lost significant body fat. The color of his fur has changed from brown to gold, and according to Nami (when she and Chopper reunite on Sabaody), the texture has gotten softer.
Chopper now wears a blue cap that has a ring of dots around the circle, while the cap has buckles hanging from it. He wears this over his old pink hat. He also wears a white and yellow vertical-striped tank top, which he takes off when he transforms into Heavy Point, and an orange pair of shorts. Aside from being slightly slimmer and having his fur changing from dark brown into a light brown color, Chopper's Brain Point form has not changed. His Walk Point (reindeer) form has grown considerably, now being roughly as tall as Usopp. His horns are larger, he has more muscle, and his fur is longer. His Heavy Point has become exceedingly larger and more muscular, being almost the size of Dosun's. He also developed new transformations through his research during the timeskip, which he debuts on Fishman Island, including Kung Fu Point (which he uses to defeat Neptune's soldiers) and a revised Horn Point (which he uses against Daruma).
While on Punk Hazard, he was given a black coat by Kin'emon using his unnamed Devil Fruit ability. He was later dressed up in samurai attire made from the same ability when the crew had departed from Punk Hazard.
At the start of the Dressrosa Arc, Chopper wore camouflage clothing. After the crew split up, he changed his headgear for the first time since the timeskip, putting on a football helmet with holes for his antlers that has three horizontal stripes running vertically down the middle, with two small ones beside one larger one, as well as large stars on each side of the helmet. He also put on a zippered coat with the same stripe pattern running horizontally all around the middle of the coat, with inverse coloration of the stripes on the helmet and a pattern of stars inside the large stripe on the coat.
During his stay on Zou, Chopper's outfit consists of his original timeskip hat with a crown on top. He wears no shirt and has a long open coat with fur and fancy jewelry attached. Upon leaving Zou, Chopper wore an open doctor's coat.