Sometimes, Putt Putt has to get food for a baby animal owned by Outback Al. A good number of them need milk (as explained by the book in the library). They're all different mammals, yet Putt Putt always brings the same kind of milk (cow milk), and it works. Although this decision was clearly made to make the game easier, it's still inaccurate - each baby mammal would need the milk from its own species.