A key difference is that Haskell functions can only have one type signature, so you need to explicitly make "Bunny" and "Lion" data constructors for "Species". Multimethods operate on multiple types. You can fake multimethods in Haskell with multi-parameter type classes (with the language extensions to allow undecidable and overlapping instances).
Does Clojure do method combinations? I was very fond of :before, :around and :after methods of the standard method combination and loved the fact that, if you really wanted to, you could have your own method combinations.
I know that "Aspect Oriented" tools support some of this stuff, but the last time I looked at those (admittedly a while ago) they seemed, at least for Java, to be pretty hacky. Not that I use Java anymore...
