EVERYDAY SCIENCE

Detailed explanation-1: -Platypus and echidnas are also mammals, but they are not marsupials.

Detailed explanation-2: -They include kangaroos, koalas (above left), tasmanian devils, wombats (above right), and other typical Australian mammals. Until recently, they also included the marsupial wolf, Thylacinus (below). Like the quagga, the marsupial wolf is now extinct. The last individual was seen in Tasmania in the 1950s.

Detailed explanation-3: -They are known as pouched mammals, because the adult females have a marsupium, or pouch. Young marsupials (called joeys) do most of their early development outside of their mother’s body, in a pouch. The pouch acts as a warm, safe place where the joeys grow.

Detailed explanation-4: -An early birth removes a developing marsupial from its mother’s body much sooner than in placental mammals; thus marsupials have not developed a complex placenta to protect the embryo from its mother’s immune system.