Barks used long-nosed rats a thugs and arch villain's hired sidekicks in various adventure stories (i.e. "Pirate Gold" as Black Pete's crew), and as unimportant background thugs in various stories, and Donald's antagonist boss in "Once Upon a Carnival".
I've been rewatching a lot of Talespin episodes lately, and it made me think of this thread (to explain that segue, Talespin was filled with a zoo's worth of anthropomorphic animal characters--bears, tigers, lions, panthers, wolves, dogs, birds, apes, pigs, hippos, rhinos, and occasional rarities like aardvarks or capybaras). As an animal-loving kid, one of my few disappointments with Duck stories was the lack of species diversity among the supporting cast. However, as an adult, I understand why Barks, who began his career drawing caricatured humans, found it easier to simply draw supporting characters who were basically human save for dog or pig noses rather than having to waste time coming up with distinctive animal designs for bit players. That said, I still cherish the occasions when Barks would draw a more unusual species in his stories, whether as a gag (like the bull and bear billionaires in "Christmas Cha-Cha") or to make a "guest" character more distinctive (like Professor Slyrat in "Missile Fissile").
I think that anthropomorphism is still somewhat of an underused tool in funny-animal comics, since it can be used to great effect, either as an effective shortcut for defining personalities based on the popular perception of the animal in question (like Gottfredson's various crabby old goat farmers in early Mickey strips or Talespin's predatory tiger arch-capitalist Shere Khan) or as the basis for humorous incongruity (like Gottfredson and Walsh's Mr. Lamb--you don't expect a proverbially innocent creature like a sheep to be a criminal mastermind). I would love to see more such creative and wider-ranging uses of the animal kingdom in Disney comics, although I can see how it might be unwelcome to those fans who prefer to think of the comics world (the Ducks' world in particular) as being basically a thinly-disguised human world. What's the other members' feeling on this? Would you like to see more critters in the comics besides dogs, pigs, and birds, or should that tradition be maintained?
In Zoo Party, booth an antropomorhpical orangutan and an antropomorhpical sloth appear at the zoo, with the gag that both "adopt" (give money to the maintenance) their non-antropomorphical counterparts.
Speaking of orangutans, Dr. Vulter is one of several Gottfredson apes. In German, he's even called "Käptn Orang".
A lot of people don't vary their birds much, but Pastrovicchio loves to draw raptors (Moldrock & Co.), and Guerrini is famous for putting in his ravens (which apparently are meant to represent Black people) and almost exclusively drawing birds in his Duckburg.