then classified as the ninth planet, Pluto, on May 1, 1930, and the attachment of that name to the dog character. Disney animator Ben Sharpsteen said "We thought the name [Rover] was too common, so we had to look for something else. ... We changed it to Pluto the Pup ... but I don't honestly remember why." Some Disney animators reportedly believed that Walt Disney chose the name to capitalize on the sensation of the newly named planet. Pluto was initially a minor character until 1934 when Disney animator Norm Ferguson gave the dog a key role in the cartoon Playful Pluto. Pluto becomes entangled with a sticky piece of flypaper, and Ferguson expanded the sequence significantly. The segment became a classic, demonstrating how Disney artists can take a simple circumstance and build humor through a character. Characterization Unlike Mickey's other animal friends, such as Goofy (who is also a dog), Pluto is a relatively normal animal, with few anthropomorphic traits apart from his facial expressions. Pluto usually does not speak in English, walk upright, or wear clothing. A significant departure from this was his speaking role in The Moose Hunt (1931), which was produced before Pluto's characterization had been clearly defined. As Pluto made more appearances, it became common that he would mostly speak in barks and grunts like most dogs. Other ways of communicating Pluto's thoughts occur through his facial expressions, and sometimes through the use of a shoulder angel/devil who speak directly to Pluto. (Mickey's Elephant, Lend a Paw). Pluto is generally a cheerful and adventurous dog, although he can be given to sheer panic when confronted with something unknown. Common themes in Pluto's stories involve him becoming jealous of Mickey getting another pet (Mickey's Elephant, Lend a Paw, Mickey and the Seal), Pluto accidentally and unwittingly swallowing something and panicking when he realizes it (Playful Pluto, Donald and Pluto), Pluto getting entangled with something inanimate like a piece of flypaper (Beach Picnic, Playful Pluto), or Pluto being pestered by a smaller animal (Private Pluto, Squatter's Rights). In many of his appearances with Mickey, Pluto will get himself into trouble and cause Mickey to get angry at him. Mickey, however, often cheers up quickly; often telling Pluto "Aw, I can't be mad at ya." Pluto sometimes appears with other regular animal characters. His friends include Fifi the Peke, Dinah the Dachshund, and Ronnie the St. Bernard Puppy.