Q&A: Marsupials vs Placentals: Why is it beneficial for marsupials to have young in a pouch from a small size, as opposed to having them develop internally as eutherians (placental mammals) do?

This article is written in response to a question from Penelope Hacker, Ashgrove, Queensland, outlined above. McAllan compares and contrasts the pros and cons of both systems. Issues of lactation, times of environmental hardship, and immunological advantages are discussed.