Thylacine (5 page)

The statistics of human-induced extinctions can be mind-boggling. During the course of the nineteenth century something like 5 billion passenger pigeons were shot in the United States, along with up to 50 million Great Plains bison killed, and almost that many pronghorn antelope. Human ingenuity and cunning aside, many lost species simply lacked defence mechanisms against humans as predator. Dodos were not stupid: they simply had no inbuilt fear of people. This is a common trait among creatures endemic to remote islands where Europeans settled, such as Hawaii, New Zealand and Madagascar. Conversely, many creatures are naturally wary of man: an instinct developed over long periods of time.

Extinction is tricky: ‘We have only the haziest idea about how many species currently exist on earth, how many there may have been in the past, and how many are going extinct at any one time'.
³

The devastation of Australia's Ice Age megafauna was swift and severe. Thirteen genera of large marsupial mammals—about 45 megafaunal species—perished. This had occurred by about 20 000 years ago, when humans were well-established on the continent. Were they hunted to extinction? If they were, perhaps the thylacine survived because it was comparatively small and also mostly nocturnal. The thylacine in fact belongs in a rare subcategory of human-agency extinction, since it was exterminated not as a food (nor in the name of sport) but because it was supposedly destroying an economic asset, namely, sheep.

Can random or background extinction explain the thylacine's disappearance from mainland Australia? This natural extinction process inevitably operates over a very long period of time and, equally inevitably, climate plays a role of some sort in it. Climate change alters growing conditions, which affect herbivores; in turn, carnivores are affected. It may be that the harshness resulting from continental Australia's aridification, and the sheer size of the continent, dispersed the thylacine gene pool to the point where introduced packs of hunting, scavenging dingoes more effectively took over the vast ‘niche'.

Dingoes came to Australia with the Aborigines, from regions to the north, not more than 12 000 years ago (when dingo-free Tasmania was cut off) and probably much more recently—about 6000 years ago.
⁴
Fossil evidence indicates that mainland thylacines were then widespread; the same evidence shows them to be extinct by about 3000 years ago. This rapid decline is of interest in itself, but is all the more intriguing for the fact that it parallels the decline of the Tasmanian devil on the mainland. Why did that strictly nocturnal, scavenging predator suffer a similar fate?

What is certain is that there have been two quite distinct thylacine extinctions, first on mainland Australia and New Guinea, and subsequently in Tasmania. There is no evidence that wild dogs competed successfully with thylacines in Tasmania after 1803—except in a cruelly oblique way, where thylacines were incorrectly blamed for dog-kills of sheep. More questionable is whether a competitor species, introduced through human agency, constitutes a ‘natural' form of competition. Given the thousands of years over which the dingo–thylacine struggle apparently took place, one could say that struggle was natural. But the later introduction to Australia by settlers of many animals, which soon became feral, was not, setting in motion as it did endemic extinctions, destabilising an already fragile environment.

Those interlopers included mice, rats, rabbits, cats, horses, donkeys, camels, goats, pigs, water buffalo, foxes and cane toads, all, apparently, robust at adapting. The mammals are all placentals, needless to say. Does this prove the point that marsupials thrived in post-Gondwana Australia only because they had no placental competition? ‘Perhaps' is not a very scientific word, but as an answer it will have to do. Contemporary feral destruction is, alas, not in doubt:

The impact of introduced mammals on the Australian environment and fauna has been very great and is exceeded only by the case of New Zealand. It may reasonably be assumed, however, that each feral mammal species has by now spread into every suitable Australian habitat and that their populations are more or less stable.
⁵

A stable feral population is proof positive that the ousting of some sensitive natives is complete. The long-term effect on the Australian biota of forced relocations or extinctions (the latter a growing list, headed by the thylacine) is not presently knowable, but there are sure to be adverse consequences. Sadly, the thylacine's demise may not represent an ecological catastrophe, or even a setback. We have lived without it. Yet if its passing means so little—and general indifference to threatened and endangered wildlife suggests so—the consequences for the future are truly grave.

A single species is estimated to have a lifespan of a few million years. This is hugely variable, but is derived from painstakingly gathered data. In the course of natural events individual species die out slowly, over thousands of years, in the converse of the evolutionary process.

Set against all of the above, and rendering them puny, are the phenomena of the mass extinctions which have governed the fate of Earthly life and are but vaguely understood. There have been about fifteen of these events, of which five are considered major, and two so gargantuan as to be named the First Event (which came at the end of the Palaeozoic era, and destroyed 90 per cent of life on the planet) and the Second Event (the extinction of the dinosaurs). Some palaeontologists and other scientists believe that the Third Event has been underway for many thousands of years—demonstrably aided and abetted by
Homo sapiens sapiens
.

The Third Event involves the consequences of thousands of years of Ice Age change—in climates and sea levels—and the impact of human evolution. Eight million years ago monkeys were diversifying rapidly. Four million years ago upright hominids were dispersing across Africa. Three million years ago, the famous Ethiopian, Lucy the australopithecine, lived in a troop, her brain not much larger than a chimp's. Two million years ago
Homo habilis
appeared, with a brain about halfway between that of a chimp and the future
Homo sapiens sapiens
. In the last 300 years, the onset of the industrial revolution, and all that has followed, has devastated the natural world, as much by its meteoric speed as by its thoroughness. Hundreds of species are dying out each day.

Carbon dioxide emissions have created global warming out of step with nature's processes for doing the same. The Earth's lungs, the tropical moist forests, are themselves headed towards extinction. One does not have to be a Third Eventist to be awestruck at our capacity to destroy without replenishing.

Meanwhile, it is no coincidence that Tasmania, the island that killed its tiger and has regretted it ever since, has much of its land mass locked away as World Heritage Area and parkland. This makes it one of the world's most protected places. Few would dispute the role of the thylacine in making that come about, as will be discussed in a later chapter.

The thylacine may be officially long gone, but other ‘extinct' animals have come back and, through global agencies such as the IUCN (International Union for Conservation of Nature) and CITES (the Convention on International Trade in Endangered Species), some imminent extinctions are being arrested— although sadly these tend to be the high-profile cases such as the panda and Russia's 40 known Siberian leopards.

Extinction reversal, as a natural return from the dead, is invariably surprising. The coelacanth, a deep-sea fish, was believed to have been extinct for 75 million years until discovered alive and well near the Comores Islands off Africa's east

The thylacine, along with the dodo, is the most prominent victim of modern human-induced species extinction. But unlike the flightless
bird of Mauritius, which became an easy food source for Dutch sailors, the thylacine was targeted as an economy-wrecking sheep killer.
(T. Peters, South Australian Museum) coast. It is unchanged in form, a Palaeozoic miracle. Ironically, nearby Madagascar has been raped of its forest cover and has possibly the inhabited world's worst extinction record. Yet in the 1980s the golden hapalemur was discovered there, a new species of lemurid. Numerous Australian marsupials and birds have been declared extinct only to be found again. The noisy scrub bird is a good example, last seen in 1899 before its rediscovery in 1961. Other returnees include the bridled nail-tailed wallaby and the sandhill dunnart and, for sheer longevity of absence, the mountain pygmy possum, believed extinct for 15 000 years.

The Angolan giant sable antelope, thought to have been rendered extinct by 30 years of sustained, brutal civil war, has been rediscovered, although there have been only five positive sightings. Angola is much larger than Tasmania. They do, however, have in common great tracts of forest which people don't enter. No doubt the antelope retreated there. It is this ability of a species to protect itself that gives so much hope to those who believe in the continued existence of the thylacine. But it doesn't offer much comfort. Life on earth took hundreds of millions of years to evolve. The rapidity, ruthlessness and extent of human-induced extinctions, of which the thylacine is just one high-profile victim, is truly frightening.

4 ‘PATHETICALLY
LITTLE IS
KNOWN'

It seems lunchtime had arrived at Adamsfield and Mr. Batiste and his partner were seated at the sheltered edge of a clearing, where they were working a sluice used to recover the alluvial osmiridium. In Mr. Batiste's own words, or as near as it is possible to get to them: ‘We heard a commotion in the bush behind, when a wallaby burst out right in front of us, bounding and weaving for dear life across the open space, closely followed by “His Nibs” in full cry . . .'

G
EOFF
A
SCHMAN,
L
INDISFARNE

W
hat, then,
is
a thylacine? Until officially declared extinct on 7 September 1986, it had the distinction of being the world's largest extant marsupial carnivore, existing only in Tasmania, the cool-temperate island state of Australia. Long part of the mainland, Tasmania became separated from the rest of the continent by a body of seawater, Bass Strait, some 12 000 years ago. That interglacial rise in sea-levels, a result of global warming, saved the thylacine, which was headed for extinction on the mainland.

Although the thylacine has always been an intriguing and controversial subject and therefore much written about, it wasn't until 1985 that the first definitive book on the animal was published, Eric Guiler's
Thylacine: The Tragedy of the Tasmanian Tiger.
It was then, and still is, a critically important account of the animal. The title of this chapter is taken from it:

Pathetically little is known of the biology of the thylacine. It is possible to make reasonable deductions from the early anatomical descriptions but we have to complete the picture from the other sketchy information available. However, this is not made easy for us as the literature contains some contradictory statements and some observations are obviously incorrect.
¹

Robert Paddle's
The Last Tasmanian Tiger: The History and
Extinction of the Thylacine
, arising out of the author's PhD thesis, is a timely and meritorious new contribution to the understanding of the thylacine, particularly in respect of attitudes towards it. The book is meticulously researched and provocative. Where Guiler cites a lack of information as the main difficulty in thylacine research, for Paddle the real stumbling block is the inconsistent and sometimes deliberately false information attending the animal before and since its demise: ‘There are ambiguities, silences, real omissions, pretended omissions and contradictions in the literature.'
²

Thus, in considering the thylacine's anatomical and behavioural characteristics, it is as well to bear in mind that fact and folklore are by definition at odds.

To begin at the beginning: the thylacine is a marsupial mammal, that is, it gives birth to tiny immature embryos which are suckled in a
marsupium
, or pouch. (Marsupials inhabit the Australian continent, which includes New Guinea and some nearby islands, as well as North and South America.) Thylacines are short-haired and tawny or tan-coloured. Their most distinctive feature is the sixteen or so dark bands running across the back and sides, in various lengths and widths, from the base of the shoulder onto the base of the tail.

Comparisons
of Silhouettes