Riversleigh is the most famous fossil formation in Australia. Dating from the Oligocene to the Miocene epochs, it bears fossils of frogs, lizards, and birds, but most notably mammals. These mammals included ancient koalas, kangaroos, precursors to the Thylacine (the Tasmanian Tiger, relatives of the Marsupial lion, and Obdurodon—a gigantic prehistoric relative of the modern platypus—among other extinct mammals from prehistory.
An episode of Walking with Beasts taking place in Australia featuring fauna from the Riversleigh fossil site was considered but was cut in the development of the series. This would have been somewhat of a spiritual successor to the Walking with Dinosaurs episode Spirits of the Ice Forest.