I used to laugh whenever I saw an ancient Volkswagen sputter through Berkeley bearing a "Reunite Gondwanaland!" bumper sticker. The idea of reassembling the southern supercontinent that began to break apart 120 million years ago seemed like a perfect parody of the improbable quests for social justice that have made my home town famous. The broad free speech demonstrations of the sixties have evolved into ever more singular quests, such as reunifying Bosnia, freeing Tibet, or trying to keep that VW bug running into the next century. Even the rebels who recently seized the diplomats in Peru had their website based in Berkeley.
Since I returned from photographing Tasmania last year, the sight of that bumper sticker makes me sad. Comparing Tasmania's pristine qualities to the condition of other fragments of Gondwanaland has given me a new perspective. Resident biologists and photographers call the island the jewel in the crown of Australia because its wild forests, coasts, mountains, and moorlands continue to hold the majority of the fauna and flora that have been rapidly disappearing from the mainland. I now see that bumper message as an epitaph for fascinating wildlife unwittingly sacrificed in our accelerating quest for a global society. As we humans meddle with life forms that have evolved in isolation, the results are all too often catastrophic. I'm considering spicing up my Berkeley commute with a larger sticker on the back of my Suburban, saying: "Stop Reuniting Gondwanaland!"
The 24 English rabbits a homesick farmer set loose in Australia in 1859 spread 70 miles a year across the continent until the population reached 750 million in 1930. Tens of millions of native creatures starved to death. At least 8000 years earlier, ancestors of the aborigines had introduced dogs to mainland Australia, causing the slow and complete demise of the unique marsupial predator now known as the Tasmanian devil. The establishment of these feral dingos also spelled doom for a much larger native marsupial predator, the thylacine, which became extinct in the wilds of the mainland about 3000 years ago. The boldly-striped creature with a hauntingly wolflike body survived as the Tasmanian tiger.
Tasmanian Mammals–A Field Guide, by Tasmania's top wildlife photographer, David Watts, lists the thylacine with a full description and reports of sightings after the last documented animal died in 1936. Though classed as extinct, the thylacine remains officially protected under a 1970 law. Accounts of more recent sightings have led to years of unsuccessful efforts to photograph them with remote cameras set up in the Tasmanian wilds. I settled for taking a picture of a color hologram at a national park visitor's center created from old black-and-white thylacine photographs.
I did photograph Tasmanian devils in the wild, thanks to David Watts, who was kind enough to allow me to use the portable blind that he had erected in prime habitat in the Asbestos Range. After dusk, I attached my Nikon to his four strobes aimed at a road-killed wallaby. Two hours later, a terrible sound erupted out of the darkness ten feet away. To my American ear, it resembled the noise that would emerge from a gunny sack into which an alley cat, a pit bull, and a handful of pepper had been tossed.
As I turned up the rheostat on the red focusing light, I made out a muscular black predator skulking toward the carcass and shot the image of the fierce creature with a bloodied snout that appears here. To my eye, the devil appeared much more canine than many recognized members of that genus certified by the American Kennel Club, though it is an unrelated marsupial that co-evolved to fill a similar predatory niche in the Australian environment.
The devil has such powerful jaws that it wholly devours kangaroos–bones, fur, and all–with loud cracking sounds. Yet the abundant kangaroos, wallabies, and wombats of the Asbestos Range have little fear of humans. I made the image of the wallaby mother with a "joey" in her pouch using a 24mm lens and fill flash, though the portrait of the more tentative wombat did require a 500mm lens.
Tasmania is something of a biological Rosetta Stone. As one of the best preserved fragments of Gondwanaland, it holds keys to understanding not only its own ancient condition but also present relationships between fragments that explain why various types of southern wildlife survive in only certain places. We citizens of the north are spoiled by living in a unique zoogeographic realm that we take for granted. Our present Holarctic region is a gift of the ice ages, during which mammals such as deer, sheep, goats, wolves, foxes, bears, and humans came to circle the globe in the northern temperate latitudes. The rest of the world is not like this, and the lesson of the severed Tasmania connection is that many of the Earth's ecosystems must be preserved as separate, but equal.
Ancient Gondwanaland slowly split apart into the continents of Africa, Antarctica, Australia, and South America, as well as smaller bits that are now Madagascar, New Zealand, Tasmania, and southern India. Many travelers to Australia return with the misguided belief that all pouched marsupials, like kangaroos and koalas, live in the south, while placental mammals that nurse their young populate the north. Never mind that native marsupial opossums are found in two-thirds of the United States or that lions and zebras live in South Africa.
The break-up of Gondwanaland started before the age of mammals was fully underway. Africa and India spun off early to connect with lands where modern placental mammals later became dominant. Marsupials actually evolved in North America, but mostly died out by 25 million years ago in the presence of the ancestors of modern lions, tigers, bears, and wolves. Before this event, some marsupials took a permanent southern vacation onto a splitting fragment that broke up into South America, Antarctica, and Australia.
Marsupial predators ruled South America in isolation until only 2 million years ago, when a row of volcanoes bridged the gap to North America. After the dust settled, the yankee invaders held far more new ground than the southern escapees. More than half the present mammals of South America come from northern placental stock, while only the southern opossum survives in the north (plus a few placental migrants, such as the armadillo).
Antarctica moved too far south to support warm-blooded land animals, while Australia drifted into splendidly temperate isolation, where marsupials thrived until humans began introducing placental life forms–rabbits, rats, dogs, and themselves. Thus began the figurative reuniting of Gondwanaland toward ecological disaster, except in isolated areas, such as Tasmania, which became an island off the southeast coast when seas rose at the end of the ice ages.
The severed connection of Tasmanian wildlife is echoed in the island's rocks, fossils, and rain forests, where more than a hundred endemic plants survive with minimal competition from exotics. Since Tasmania's amazing landscapes and botanical life deserve a story all their own, stay tuned next month for a feature article in addition to my regular column.