For nearly a hundred years, fans have been trying to find the answer to one of life's most puzzling Disney questions: What kind of animal is Goofy? It should be pretty cut and dry, especially when taking his friends into account. Mickey is clearly a mouse, just as obviously as Donald is a duck, and their surnames confirm that. Goofy's surname, however, offers no insight into his species; it's simply Goof, suggesting he's little more than a silly being created solely for the purpose of making others laugh. Interestingly, Goofy Goof wasn't always the fun-loving character's name. He was originally called Dippy Dawg, so perhaps there is a clue about his species after all. Or maybe not.
Source：https://www.cbr.com/what-animal-is-goofy/
