marsupial

In recent years, scientists have aimed to clone the Tasmanian tiger or thylacine, an extinct marsupial.

There are also jobs for truffle hunters, "wine whisperers" and wombat walkers willing to take the marsupials "on their morning waddle".

Large marsupials like kangaroos and wallabies tended to avoid burrows, unless they had been flooded with rainwater; then they used them as watering holes.

The reverse trek was made by four different kinds of ground sloths, oversized armadillos, terror birds, capybaras and even a marsupial.

"They show the world that long before Australia became the land of pouched mammals, marsupials, this was a land of furry egg-layers - monotremes," Ms Smith says.