. . . I've always thought that even if it was a cop-out, it was at least a stylistically distinct cop-out.
that said, If you're allergic to squirrels, Doc, I could see Larry and Darryl as Labradors or other well-meaning but generally clueless breed of dog. (Peek-n-sneeze? Chiwowowowas?)
That said: domestic cats make pretty good foils, too. . . . and they have plenty of options for markings, just to keep you from getting bored.