There is a place in Australia where you can touch this story; it’s my favourite place. This wilderness paradise on the south-eastern corner of Australia is called far East Gippsland; it was one of the last places connected to Gondwana. If you stand on a beach looking southwards over the Southern Ocean you can imagine Gondwana peeling away into the distance. All around you can see the outcome of this stupendous rift: well over 300 species of birds; a cornucopia of marsupials including koalas, wombats, wallabies and kangaroos; reptiles in abundance; relict Gondwanan rainforests; vast tracts of eucalyptus forest (including the world’s tallest flowering plants: Eucalyptus regnans). On land you will rarely find placental mammals but the Southern Ocean is home to whales, dolphins and seals living with a super abundance of petrels, albatrosses and other pelagics.
How did this all happen? During the early stages of its evolution as a continent Australia was connected to Antarctica thence to South America (which, importantly, had yet to collide with North America). It was much warmer than today meaning this enormous land mass was rich in plants and wildlife which moved across, through and around it at will - this is the reason South America has marsupials and many plants similar to those found in Australia.
When the three continents separated another profoundly significant event in the earth’s history occurred; the seas of the southern hemisphere united. Global rotation set up a circumpolar current that revolved (and continues to revolve) around the globe faster than any other ocean current; it stopped all warm tropical currents moving southwards. As a spectacular result Antarctica froze. Soon after South America hit North America and was invaded by northern wildlife and plants, changing the continent forever. Australia meandered northwards, isolated from all other places, a breeding ground for the unique and the unusual.
As Australia tore away from Gondwana, Nature was perfecting two major creations - flowering plants and mammals - and she used the isolated continent of Australia as a laboratory to craft a distinctive suite of masterpieces. Examples include the genus eucalyptus with +600 species containing the most prolifically flowering trees on earth (they don’t have petals but are rich in pollen and nectar!); then she created +70 species of honeyeaters dedicated to pollinating the flowers and tossed in 35 lorikeets for support. These same trees and their food (pollen, nectar and seeds) helped produce the songbirds of the planet (including the lyrebird, the greatest of them all) and many of the world’s cockatoos.
Nature broke all the boundaries when she started work on Australia’s mammals. She had a few prototypes to fool about with - tiny placentals and monotremes - and came up with a staggering array of marsupials which has included carnivores as big, powerful and dangerous as a tiger, a giant meat-eating kangaroo, and a herbivore the size of a hippopotamus! Like most megafauna these guys have gone but their genetic heritage lives on today in over 150 marsupials including my favourite, Macropus giganteus, the Eastern-grey kangaroo.