Has anybody ever traced the history of human characters in short cartoons? I specifically mean the use of humans as supporting characters in cartoons that are about anthropomorphic animal characters.
For many years, if a cartoon was about a talking animal character, then everybody else in the cartoon would be a talking animal as well. Characters were only drawn as humans if there was some specific reason why they wouldn't work any other way. Like Disney's "The Brave Little Tailor": Mickey is a talking animal; every character he meets in the first part of the film is a talking animal; only the giant is a human, because the term implies a giant human being, not a giant animal.
Now look at a cartoon like "No Hunting," which I wrote about a few weeks back (and if you haven't looked at it, buy or borrow the Chronological Donald Duck Vol. 4 and look at it now). In that cartoon, everybody is a human except Donald, his grandfather, and any animals that are actually supposed to be animals: cows, deer and so on. By the '50s, the rule had completely changed for short cartoons: whereas it was once thought that talking animals should live in a world of talking animals, it became the norm to have your talking animal character surrounded by humans.
One thing that led to this was the development of animal characters who were not quite as humanized as Mickey Mouse. Mickey, and Porky Pig, are basically humans who happen to be drawn as animals. They live like humans, they act like humans, they own animals as pets. The cartoon stars who emerged in the '40s were often animals who actually lived like animals: Tom and Jerry acted like a cat and mouse; Bugs Bunny lives in a hole in the ground, eats carrots, and is menaced by hunters. (These characters are, for the most part, naked, whereas Mickey and Porky and Donald wear clothes.) With a character like Bugs, his adversaries have to be human, and when they're not, they have to be animal-like animals, like hunting dogs or Tasmanian Devils. It wouldn't work if Elmer Fudd were drawn as a dog who happens to go hunting with a gun. The whole thing that makes Bugs work as a character is that he is, as he says, "a rabbit in a human woild." Other factors include the rise of the UPA style, making human characters the in thing.
Not that critter casts ever completely went away. I remember seeing "Daffy Dilly" for the first time and being surprised that the butler in that cartoon was drawn as a dog. I guess they felt that since Daffy had a human-type job in that cartoon, other human-type jobs should be occupied by animals; similarly, in "The Stupor Salesman," Daffy is a salesman and Slug McSlug is an animal character. It's fair to say that if those cartoons had been made a few years later, those characters would have been humans. But Tex Avery was still doing humanized animal cartoons like "Magical Maestro" into the '50s. So it didn't go away, it just beame the exception rather than the rule.