Australia's fauna consists of a wide variety of animals. Some 83% of mammals, 89% of reptiles, 90% of fish and insects and 93% of amphibians that inhabit this landmass are endémiques1. This high level of endemism can be attributed to the large geographic isolation from the mainland, its tectonic stability, the effects of an unusual pattern of climate change on soil and flora over geological time. One of the specificities of the Australian fauna is the relative scarcity of placental mammals. This is why the marsupials, a group of mammals whose young are carried in a marsupium and includes kangaroos, possums, koalas and dasyuromorphia occupy many ecological niches that in other parts of the world are occupied by placental animals. Australia is home to two of the five extant species of monotremes known. She has numerous venomous species, including the platypus, some spiders, scorpions, octopus, Scyphozoa, some molluscs, stonefish and stingrays. Australia is the only part of the world where venomous snake species outnumber the species of non-poisonous snakes
