Tasmanian Devil by David Owen Read Free Book Online

Southern Oscillation, the former disrupting the regular rainfall patterns of the latter through cooling of the upper layer of the southern Pacific Ocean. The result across eastern Australia in particular is drought, sustained over perhaps five years before returning warm sea currents create heavy rains and floods. It’s unpredictable and harsh, and the continent’s arid-adapted wildlife reflects that. But there are a few exceptions. The Daintree tropical rainforest system in far northeast Queensland supports abundant and complex populations of flora and fauna, while Tasmania, a significant area of which is Gondwanan remnant forest, supported the carnivorous devil, thylacine and eastern quoll after their mainland extinctions.
    Proponents of the human interference theory believe that migrating waves of people slaughtered the megafauna to such an extent that they became extinct. This would have to have taken place well before the peak in late Ice Age climate aridity (to disprove climate as the culprit), and suggestions are that the megafauna began to be slaughtered about 46 000 years ago. This so-called Blitzkrieg hypothesis infers swift and rampant overkilling, as seemingly happened with the New Zealand moas and North America’s mammoths and mastodons. A less bloodthirsty explanation is that regular slaughter for consumption, together with the introduction of fire management, which significantly altered grazing and browsing habitats, induced the same extinction result but over a far longer period. In this context, Stephen Wroe contends that a significant mid-Holocene increase in human land usage could have been a primary cause. 9
    Did the devil survive because of its comparatively small size and ability to become even smaller (dwarfism)? Or was its place in the ecosystem assured because it was capable of both hunting and scavenging? Even in the absence of easy-to-catch megafauna, did people not hunt it? Why did the thylacine survive but not the larger marsupial lion?
    The subsequent extinction of the devil across mainland Australia is also hard to explain. It appears the animal survived there until as recently as 500 years ago, although the introduction of dingoes some 6000 years ago is generally considered to have marked the beginning of their end. Their predator– scavenger niches overlap; dingoes will forage for young devils; and there have never been dingoes in Tasmania.
    There may in addition have been a climatic factor. Devils thrive in temperate, well-covered Tasmania with its abundance of prey in a relatively compact area. Much of mainland Australia, on the other hand, has become an ever more arid and inhospitable environment since the devil survived the megafaunal extinction. Perhaps those conditions affected the mainland species over thousands of years until it was reduced to remnant populations in the east and southeast. Then, and only then, might the devil have succumbed to the dingo.

    Skeleton of Sarcophilus harrisii , the Tasmanian devil. (Courtesy Collection Tasmanian Museum and Art Gallery)
    Megafauna-era butchering tools include scrapers of all kinds as well as axes, but it was not until some 10 000 years ago that the Aboriginal people became true hunters, with the invention of the boomerang and spear. It is suggested that prior to those technological advances, animal-taking must have been somewhat opportunistic. The famous Devil’s Lair cave in south-west Western Australia, named for the extinct Tasmanian devil bones found in it, provides a clue.
    Devil’s Lair cave is one of the most important in Australian archaeology. By dating human occupation back some 45 000 years, 10 it confirms a much earlier human presence in the arid centre. Human markings on the walls may be the oldest on the continent. Cultural artefacts of bone and marl are also among the oldest known. Many extinct species are represented, but it appears that giant kangaroos were the primary food item, followed by wallabies