Iwao Takamoto, the animator who created the beloved Scooby-Doo and directed the cartoon classic Charlotte's Web, has died. He was 81.

Takamoto died Monday of heart failure at Cedars-Sinai Medical Center, Warner Bros. spokesman Gary Miereanu said.

In a career that spanned more than six decades, Takamoto assisted in the designs of some of the biggest animated features and television shows for Disney and the Hanna-Barbera animation team. They included Cinderella, Peter Pan, Lady and the Tramp, 101 Dalmatians, The Jetsons and The Flintstones.

But it was his creation of Scooby-Doo, the cowardly dog with an adventurous heart, that captivated audiences and endured for generations.

Takamoto said he created Scooby-Doo after talking with a Great Dane breeder and named him after Frank Sinatra's final phrase in Strangers in the Night.

The breeder "showed me some pictures and talked about the important points of a Great Dane, like a straight back, straight legs, small chin and such," Takamoto said in a recent talk at Cartoon Network Studios.

"I decided to go the opposite and gave him a hump back, bowed legs, big chin and such. Even his colour is wrong."

Takamoto also created other famous cartoon dogs such as Astro from The Jetsons and Muttley, the mixed-breed that appeared in several Hanna-Barbera animations. He also directed the 1973 feature Charlotte's Web.

Born in Los Angeles to parents who had emigrated from Japan, Takamoto graduated high school when the Second World War began. He and his family were sent to the Manzanar internment camp in the California desert, where he learned the art of illustration from fellow internees.

Despite a lack of formal training, he landed an interview with Walt Disney Studios when he returned to Los Angeles and was hired as an apprentice.

Takamoto worked under the tutelage of Disney's "nine old men," the studio's team of legendary animators responsible for its biggest full-length films before moving to Hanna-Barbera Studios in 1961. There he worked on cartoons for television, including Josie and the Pussy Cats, The Great Grape Ape Show, Harlem Globe Trotters and The Secret Squirrel Show.

Takamoto was survived by his wife, Barbara, son Michael and stepdaughter Leslie.

Funeral arrangements were pending.