Mammals with pouches, like kangaroos and koalas, have a radical evolutionary history that suggests they are "more evolved" than previously thought, a new study finds.
Marsupials used to be considered an evolutionary stepping stone between egg-laying mammals called monotremes, such as platypuses, and placental mammals, such as humans, according to the new study. While modern science now recognizes that marsupials and placentals evolved from a common ancestor around 160 million years ago, the authors argue that marsupials retain a slight stigma from the days when they were classified as an intermediary.
