Accidentally Correct Zoology: In the book series the protagonist is raised by a fictional ape species named "Mangani", which combines the physical and behavioral traits of chimpanzees, gorillas and primitive humans. In 1996, in the Bili Forest in the Democratic Republic of Congo, a subspecies of chimpanzee was discovered that is larger than other chimpanzees and shows some gorilla-like behavior. The similarity between the Mangani and the "Bili ape" did not go unnoticed.
Dueling Works: Due to complex licensing issues related to the character, during the run of the Johnny Weissmuller films made by MGM, no less than four competing films and serials by other studios were released, including one starring Buster Crabbe, two starring Herman Brix, and another starring Glenn Morris. It happened again during the Gordon Scott era in 1959 when a competing Tarzan reboot film starring Denny Miller was released.
The Disney movie
Awesome, Dear Boy: Rosie O'Donnell had always wanted to voice a character in a Disney animated movie.
Cut Song: A few songs cut from the film were actually demo versions of the songs that later appeared in the film. One notable mention goes towards "6/8 Intro" which was actually Phil Collins' proposition as to how the music in the film should sound. Another one is "I Will Follow" which served as a precursor to "Strangers Like Me", but it sounds more like Tarzan is trying to make Jane feel happy.
Animator Ken Duncan has shared some unused animation scenes cut from the film, including Jane's original intro (when coming out of the bamboo, her dress is flipped to make her look pregnant) and Jane politely asking Tarzan to let her go in the middle of the baboon chase sequence.
Originally, Sabor was shown killing Tarzan's father in the beginning of the movie, but the scene was removed.
Dueling Movies: With The Iron Giant, though it was hardly a duel. This was mostly due to marketing, however, as Giant had a mere four months of advertising from an apathetic studio while Tarzan was being heavily plugged a year in advance. Things turned out better for Giant in the end, as it eventually became a massive Cult Classic while Tarzan merely became a footnote on Disney's history.
Science Marches On: The main reason Disney changed the Mangani to gorillas is because of this: Gorillas have been found to be the Gentle Giants of the jungle, and thus perfect animals for a Disney film.
The scene where Jane was ranting about what happened to her, her father and Clayton, after being rescued from the baboons? That whole thing was improvised by her voice actor, Minnie Driver.
Likewise much of Professor Porter's reaction to her ranting was improvised along with other lines such as "Oh, just like Aunt Isabelle" when Jane describes how Tarzan walks.
On a production level, the original plan was to just have Tony Goldwyn do the classic Tarzan yodel but he was unable to provide a satisfactory version of it. When the topic came up during a conversation between the producers and Brian Blessed after production had wrapped up, Brian told them he could do the yodel, as he used to do it as a child. When the producers didn't believe him, he did the yodel on the spot. The producers were so impressed they canceled his ride to the airport and had him sign a separate contract for the yodel and him record it right then and there.