Chopper is na�ve and super timid, often acting like a child because he doesn't know any better.

Like Luffy, he is easily impressed at things like beams, cannons, and hidden abilities. He is a coward at times like Usopp and Nami,

although his cowardice can be attributed to his childishness and overall lack of trust in his own fighting skills

(a contrast to Nami's self-survival based cowardice and Usopp's insecurity based cowardice). Chopper is more or less on a journey to define himself,

seeing almost anyone on his team as a role model and in some cases, imitate their behavior, especially Usopp.

He is an upright friend and companion who will try anything to overcome a task given by his team.

He still has a feeling of distrust for humans from his youth and will often outright insult and claim that compliments don't make him happy

to a human who compliments him while obviously being happy about it (he starts to do the "Dirty Old Man" dance which was a bit by famous

Japanese comedian Ken Shimura) which became a running gag. Chopper seems to be very forgiving of those close to him, for when Usopp wanted

to rejoin the crew at the end of the Enies Lobby Arc, he called out to Luffy and Zoro, although they were ignoring him completely.

He would rather run and hide than fight, but becomes more courageous when others are there to support him.

His dream is to carry out his deceased mentor, Hiluluk's belief that there is no incurable disease, and to become a doctor that can cure any illness.

To this end, his childish nature vanishes whenever his medical skills are required; he doesn't hesitate in the least in any actions regarding

the well-being of his patients. Chopper also has the strong belief that a doctor is supposed to help save people, and becomes angered when somebody

treats life so casually. This was why he was greatly angered at his former hero, Dr. Hogback, when the man treated the patients and Zombies lives,

and deaths, so callously. He was also enraged at Caesar Clown, for kidnapping and experimenting on children, and making them addicted to drugs.

Another one of Chopper's habits is his reverse cartoon peek, where he stands behind a wall or a doorway and peeks at people, trying not to be seen by them.

Unfortunately he's not hiding his body behind the wall, as a result his body is visible and only one half of his face is hidden.

A running gag is that Chopper will believe just about anything he hears, making him easy prey for Usopp's stories.

He also believed Nami when she lied to Lola about being a man, even though the truth was very obvious. In fact, until Jinbe stated otherwise,

he thought that the captains duty was not to listen to anyone. When there is someone who is injured he always panics and screams "Call a doctor!!".

It isn't until he figures out that he is the doctor or when one of his nakama hits him that he starts to tend to the injured person

(he seems to have stopped doing this after the two year timeskip). Another one is when he (and Brook) jumps into the water without hesitating

to save Luffy from drowning, only to drown with him (since the Devil Fruit that he ate makes it impossible for him to swim).

He, together with Brook and Luffy, ends up being saved by the other members of the crew. After the timeskip,

Chopper seems to have grown more confident, much like Usopp. He no longer strives to be looked at as a human,

now only wanting to "be a monster that can help Luffy" as he put it. He even has grown mature enough to smack his nakama,

mostly Zoro and Luffy, when they try to do something stupid.