<P> Buster Baxter (voiced by Daniel Brochu) is Arthur's best friend . He is a white rabbit who wears a turquoise long - sleeve shirt and dark jeans . He suffers from asthma . He is also obsessed with aliens . He is interested in comedy, action figures, is an amateur private investigator, and plays the tuba . He loves eating, gardens, studies food ingredients, and keeps expired food in his room and school desk . He has no siblings and his parents got a divorce when Buster was younger . He created and celebrates a no - frills holiday called "Baxter Day". His father travels the world from working as a pilot, and as a result they were given a spin - off series, Postcards from Buster . A running gag is Buster being unable to keep a secret, getting his friends into trouble or ridicule . </P> <P> Francine Alice Frensky (voiced by Jodie Resther) is a monkey . She has short brown hair, clipped back with 2 barrettes, blue jeans, and a maroon sweater . Francine is tomboyish, athletic, sings, and plays the drums . Her family is devoutly Jewish, and observe Yom Kippur and Hanukkah . Her best friend is Muffy, who shares her middle name . </P> <P> Alan Powers (voiced by Luke Reid 1996--1999; Steven Crowder 2000--2001; Alex Hood 2002--2005; Paul - Stuart Brown 2004--2007; James Buckholder 2006; Lyle O'Donohue 2008--2012; Siam Yu 2012--2014; Max Friedman Cole 2014--present), usually known by his nickname "The Brain", is a bear of Senegalese descent, and celebrates Kwanzaa . He usually wears a grey sweater . As his nickname suggests, he is multi-talented, excelling both academically and athletically . He has an innate interest in science, and does not believe in any theory until it is proven with concrete evidence . He also assists his mother in a large ice cream parlor . He plays the cello in the class band </P> <P> Mary Alice Crosswire, known better by her nickname Muffy (Melissa Altro), is a monkey who usually wears a purple & white dress . She is the spoiled daughter of Ed Crosswire, a wealthy entrepreneur, and has an older brother named Chip . Because of her wealthy background, Muffy can be rather haughty and often tries to take credit for other people's work . Nevertheless, she usually learns her lessons in hubris and enjoys spending time with her friends outside the family mansion . </P>

What kind of animal is brain from arthur