When Australia separated from the continental landmass, there were no eutherian mammals living in its territory. And the vast island drifted north, leaving the marsupials and the monotremes free from competitors.
Everything began with a great journey across the Indian Ocean, millions of years ago.
This was just the beginning of the great marsupial adventure, a period of enormous changes.
On its journey northwards, Australia became increasingly warm, and its jungles became smaller. The climate of the island slowly changed. The plants had to adapt or die. New species gave birth to new forests, more open, and without the splendour of the old jungles, but composed of experts in survival. And the old plants of the southern supercontinent gave way to others, more modern, and much more effective – flowering plants.
Flowering plants and more open spaces had immediate consequences for the zoology of Australia. The new forests were more accessible than the jungles, and the flowers were attractive, appetising, and highly nutritious food sources. And very soon, animals arrived to eat them.
The number of insects rapidly multiplied, and became valuable allies in pollination. So, the plants also benefited, and spread throughout the length and breadth of the drifting continent.
For the birds, the change was a two-fold advantage, because many of them fed on the ever more numerous insects, while for others the flowers were valuable sources of energy. And like the birds, the mammals also took advantage of this constant increase in resources.
The hare wallabies made double use of the bush forests. Not only did they eat the flowers, fruits and shoots, but they also found here a safe refuge in which to live.
This spectacled hare wallaby- is marking its territory in the full light of day. Once the enormous lizards of Gondwana had disappeared, the daylight hours were free from these colossal competitors, and some marsupials became diurnal.
The quokka is a survivor of the changing forests. Although it prefers the dense jungles, in the new bush forests it found sufficient vegetation to survive, and ended up colonising them.
The numbat, on the other hand, specialised in obtaining food from a source not exploited by any other marsupial. It is today the only animal in Australia which feeds on termites, an excellent way of avoiding competition. But not everything was easy for these small, adaptable mammals of the island of Australia.
Sooner or later, the food chain had to be completed, and with so many small animals available, it was not long before predators appeared.
The olive-coloured python is a real all-rounder. Small marsupials, lizards, tiny birds and reptile eggs all form part of its diet, and it is equally adept at hunting on the ground, or in the trees.
Each change in the climate meant a change in the vegetation, and each one of these was followed by an endless number of adaptations by the animals.