Jungle Cruise skippers memorize hundreds of “corny dad jokes” for use in the Disneyland attraction spiel, according to “The Happiest Story on Earth” special on ABC’s “20/20” newsmagazine TV show. “When we hand our brand new skippers that spiel, it can be intimidating because there are 600 jokes,” Disneyland Jungle Cruise Skipper Kristi Newsander said on “20/20.”Sign up for our Park Life newsletter and find out what’s new and interesting every week at Southern California’s theme parks. Subscribe hereALSO SEE: Disneyland spends $600,000 to replace Jungle Cruise animatronic tiger sceneThe Jungle Cruise ride that debuted on July 17, 1955 with the grand opening of the Anaheim theme park was inspired by Walt Disney’s True-Life Adventures nature documentary films and “The African Queen” adventure film from 1951. The skippers added jokes to the official script in the 1960s after Walt Disney asked animator Marc Davis to sketch some new scenes that would introduce more drama and humor to the ride. ALSO SEE: Disneyland’s Jungle Cruise lacks one thing Walt Disney really wanted: Live animalsAt least eight Jungle Cruise skippers who refused to stick to the script were fired in 1997 after a crackdown by Disneyland on unauthorized jokes, according to the Los Angeles Times.