I know what you’re thinking after reading that headline: How lazy were Disney animators back in the day? Were they so tired from Walt Disney harping on them and abusing them that they just called it a day and copied existing work? Well, maybe they were exhausted, but that was more likely because before computers could animate full-length movies, animators had to hand-draw every single movement to make drawings appear to move. And in the early days, models were brought in and filmed as a reference for the animators, who would draw the characters over their real-life counterparts. That was time and money, so the decision was made to reuse some generic dancing scenes, as the video above shows.
Here is a video of the reference models used in several early Disney movies, set to some music that is enough to make a true Disnerd nostalgic:
This newsreel from 1938 explored the process behind Disney’s first full-length feature Snow White and the Seven Dwarfs, which was groundbreaking at the time. It is quite involved, to say the least. And please pardon the casual sexism.