You know, it's strange... I was thinking about Porky Pig just today, and about how, throughout his pen and ink "career", the staff at WB appear to have not really known what to do with him.
In cartoons like Tashlin's "Wholly Smoke", Jones's "Old Glory", Clampett's "The Film Fan" and "Porky, and even in his very first cartoon, "I Haven't Got a Hat"; he was depicted as a child.
In other cartoons like Tashlin's "Porky's Romance", Clampett's "Porky and Daffy" and "The Daffy Doc", and Avery's "Gold Diggers of '49" he's depicted as an adult pig (and most of the time a really unattractive-looking one).
These cartoons were all made between 1936 and 1939... It wasn't until around 1940 or 41 that they seem to have settled upon keeping him as an adult (albeit a child-like one).
Bugs Bunny and Daffy Duck, on the other hand, appear to have been conceived as adult characters from the very start.
This post is brought to you by "Raisin d'etre", the delicious, high-fiber breakfast cereal for existentialists.