One of Walt Disney's main competitors was Max Fleischer, the head of Fleischer Studios, which produced cartoons for Paramount Pictures. Fleischer Studios was a family-owned business, operated by Max Fleischer and his younger brother Dave Fleischer, who supervised the production of the cartoons. The Fleischers scored successful hits with the "Betty Boop" cartoons and the "Popeye the Sailor" series. Popeye's popularity during the 1930s rivaled Mickey Mouse at times, and Popeye fan clubs sprang up across the country in imitation of Mickey's fan clubs; in 1935, polls showed that Popeye was even more popular than Mickey Mouse. However, during the early 1930s, stricter censorship rules enforced by the new Production Code in 1934 required animation producers to remove risqué humor. The Fleischers, in particular, had to tone down the content of their Betty Boop cartoons, which waned in popularity afterwards. The Fleischers also had produced a number of "Color Classics" cartoons during the 1930s which attempted to emulate Walt Disney's use of color, but the series was not a success.