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Australian megafauna comprises a number of large animal species in Australia, often defined as species with body mass estimates of greater than 45 kilograms or equal to or greater than 30% greater body mass than their closest living relatives. Many of these species became extinct during the Pleistocene (16,100±100 – 50,000 years BC).〔Vanderwal and Fullager 1989 as cited in Josephine Flood (2004) Archaeology of the Dreamtime, J.B Publishing, Marleston p, 182 ISBN 1-876622-50-4〕 The cause of the extinction is an active, contentious and factionalised field of research where politics and ideology often takes precedence over scientific evidence.〔Claudio Tuniz, Richard Gillespie, Cheryl Jones ''The Bone Readers: Atoms, Genes and the Politics of Australia's Deep Past'' Allen & Unwin 2009 ISBN 9781741147285 Pg 14〕 It is hypothesised that with the arrival of early Australian Aboriginals (around 48,000–60,000 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. Some proponents claim a change in the climate alone caused extinction of the megafauna, but these arguments have to account for the fact that megafaunal species comfortably survived two million years of climatic oscillations, including a number of arid glacial periods, before their sudden extinction. 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 of 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. 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 Australian Aborigines appear to have rapidly eliminated the megafauna of Tasmania about 41,000 years ago (following formation of a land bridge to Australia about 43,000 years ago as ice age sea levels declined) without using fire to modify the environment there, implying that at least in this case hunting was the most important factor. It has also been suggested that the vegetational changes that occurred on the mainland were a consequence, rather than a cause, of the elimination of the megafauna.〔 This idea is supported by sediment cores from Lynch's Crater in Queensland, which indicate that fire increased in the local ecosystem about a century after the disappearance of megafaunal browsers, leading to a subsequent transition to fire-tolerant sclerophyll vegetation. There are similarities between prehistoric Australian megafauna and some mythical creatures from the Aboriginal dreamtime (Mackness 2009). == Living Australian megafauna == The term "megafauna" is usually applied to large animals (over 100 kg). In Australia, however, megafauna were never as large as those found on other continents, and so a more lenient criterion of over 40 kg is often applied〔Danielle Clode (2009) Prehistoric giants: the megafauna of Australia, Museum Victoria ISBN 978-0-9803813-2-0〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Australian megafauna」の詳細全文を読む スポンサード リンク
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