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".

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).