The term Australian megafauna refers to the megafauna in Australia during the Pleistocene Epoch. Most of these species became extinct during the latter half of the Pleistocene, and the roles of human and climatic factors in their extinction are contested. There are similarities between the prehistoric Australian megafauna and some mythical creatures from the Aboriginal Dreamtime. Causes of extinction Many modern researchers, including Tim Flannery, think that with the arrival of early Aboriginal Australians (around 70,000~65,000 years ago), hunting and the use of fire to manage their environment may have contributed to the extinction of the megafauna. Increased aridity during peak glaciation (about 18,000 years ago) may have also contributed, but most of the megafauna were already extinct by this time. Others, including Steve Wroe, note that records in the Australian Pleistocene are rare, and there is not enough data to definitively determine the time of extinction of many of the species, with many of the species having no confirmed record within the last 100,000 years. They suggest that many of the extinctions had been staggered over the course of the late Middle Pleistocene and early Late Pleistocene, prior to human arrival, due to climatic stress. New evidence based on accurate optically stimulated luminescence and uranium-thorium dating of megafaunal remains suggests that humans were the ultimate cause of the extinction for some of the megafauna in Australia. The dates derived show that all forms of megafauna on the Australian mainland became extinct in the same rapid timeframe—approximately 46,000 years ago—the period when the earliest humans first arrived in Australia (around 70,000~65,000 years ago long chronology and 50,000 years ago short chronology). However, these results were subsequently disputed, with another study showing that 50 of 88 megafaunal species have no dates postdating the penultimate glacial maxiumum around 130,000 years ago, and there was only firm evidence for overlap of 8-14 megafaunal species with people. Analysis of oxygen and carbon isotopes from teeth of megafauna indicate the regional climates at the time of extinction were similar to arid regional climates of today and that the megafauna were well adapted to arid climates. The dates derived have been interpreted as suggesting that the main mechanism for extinction was human burning of a landscape that was then much less fire-adapted; oxygen and carbon isotopes of teeth indicate sudden, drastic, non-climate-related changes in vegetation and in the diet of surviving marsupial species. However, early Aboriginal