Macropus giganteus Click to enlarge image
Eastern Grey, Mother and young Image: Denise Greig
Australian Museum

There are over 330 species of marsupials. Around two-thirds of them live in Australia. The other third live mostly in South America

A marsupial is born in a very incomplete state. They are minute, blond, hairless and with hindlimbs only partially formed. The forelimbs however are developed, and the toes are armed with sharp, curved claws. They use these claws to make the journey to the pouch, many times the body length of the one month old foetus.

Marsupials have a short-lived placenta that nourishes their young for just a few days before they’re born, the rest of their nutrition coming from the mother’s teats inside the pouch. Instead of the placenta, the mother’s milk nourishes the young and allows it to grow and develop.

Although the word ‘marsupial’ comes from the Latin word ‘marsupium’, which means pouch, not all marsupials have pouches. The pouch is designed to protect the offspring while they suckle on the nipples, however some in some species this is just a fold, not something the young can fit inside for their joey stage of development.

Marsupials have an extra pubic bone, the epipubic bone, to support their pouch.

The toes of many marsupials appear conjoined with webbing, a mutation known as syndactyly. The koala is a perfect example.

Australian marsupials can be categorised by what they eat into 3 groups:

  1. Dasyurids - these are the meat-eating marsupials: quolls, the tamanian devil, tasmanian tiger, numbats, dunnarts, antechinus.
  2. Peramelemorphs - these are the omnivorous marsupials: bilbies and bandicoots.
  3. Diprotodonts - these are the largely herbivorous marsupials: kangaroos, wallabies, possums, koalas, wombats.