Australia’s strange marsupials were for many years viewed as ‘inferior’ or ‘second-class mammals’ because of their universal habit of producing only tiny, helpless young, attributed to their lack of a ‘true’ placenta capable of nourishing a larger offspring. Research initiated on the quokka wallaby by the late Harry Waring led to a well-spring of studies on their reproduction, nutrition and ecology and a deeper understanding of their alternate mode of survival in an environment very different from that inhabited by other mammals in the northern hemisphere. The legacy of these pioneers has been built on by others and ongoing research on marsupials has made unique contributions to our understanding of placental function, blastocyst development and sex determination in mammals.