Post by Don Smith on May 7, 2007 0:45:22 GMT -5
SPIEGEL ONLINE - May 4, 2007, 04:05 PM
URL: www.spiegel.de/international/zeitgeist/0,1518,481065,00.html
THE DEVIL IS DYING
Mysterious Facial Cancer Threatens Symbol of Tasmania
By Rafaela von Bredow
The Tasmanian Devil, an icon of the island after which it is named, is on the verge of extinction as a contagious facial cancer decimates the animals. It's an epidemic of a kind never seen before and scientists are desperately trying to create a vaccine.
AFP
A Tasmanian Devil: a jaw almost as strong as leopard
The birth of Tasmanian devils, which are furless and smaller than crabs when they are born, usually comes 21 days after conception.
Four of the miniature devils fit in the pouch of a female, where they spend about 21 weeks growing, firmly clinging to the mother's teats. The young ride out the cool winter of the southern hemisphere in these cozy surroundings, first venturing outdoors at the beginning of spring.
Strict conformity to the rhythm of the seasons is important for Tasmanian Devils, the largest carnivores among marsupials. And yet biologists are starting to observe individual animals that are no longer sticking to the normal order of things for their species, which has ensured their survival on the Australian island for many thousands of years. They are mating too early in their lives, and their offspring are born in the wrong season.
FROM THE MAGAZINE
Find out how you can reprint this DER SPIEGEL article in your publication. The cause is a disease that has turned the lives of Tasmanian Devils upside down. A mysterious form of cancer has afflicted the animals. Since the discovery of the first sick animal 11 years ago, the strange tumors have grown rampant in and killed more than 75,000 of the jet-black carrion eaters, or about half of all "Tassie Devils," as the raccoon-sized creatures are affectionately called by Tasmanians.
The cancer is fatal for the animals. "Once they've got a lump, it's a one way trip," says Menna Jones, an expert on Tasmanian Devils at the University of Tasmania. "It is extremely unusual to have this extreme degree of death," explains Nick Mooney, a wildlife biologist with the Tasmanian government.
Extinction soon?
What has scientists and species protection experts especially worried is that the tumors are contagious. Like greedy parasites, the diseased cells can jump from one animal to another, where they grow and eventually dissolve its bones, muscles and tendons like an acid bath.
DER SPIEGEL
Graphic: Cases of DFTD cancer in Tasmanian devils
There has never been a type of cancer like this and it is spreading like the plague. The disease reached the Freycinet Peninsula in 2001, and within 18 months all the adult Tasmanian Devils there died. The disease is already present on almost two-thirds of the island, which is about the size of the German state of Bavaria. In the northeast, where the disease was first detected, it has already wiped out 90 percent of the marsupial carnivores.
It is now clear that the Tasmanian Devil, an icon and tourist attraction for the island, will become extinct unless the cancer can be stopped. "That would be unforgivable," says ecologist Mooney.
Residents of the island still feel a deep sense of guilt about the Tasmanian Tiger, a larger relative of the Devil, which farmers mercilessly hunted, poisoned and finally wiped out. The last Tasmanian Tiger died in a zoo in 1936.
As a result, the Tasmanian Devil, as the largest remaining marsupial carnivore, acquired the status of a symbol of the Australian island's precious fauna, which was urgently in need of protection. Indeed, it is fascinating how the Tasmanian Devil fills a similar niche as the hyena in Africa. Even the way the two animals lollop is similar.
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The Devils are believed to have acquired their name from the first Europeans who settled the island, formerly known as Van Diemen's Land, in the early 19th century. It is not difficult to imagine how they arrived at the name. Even the nighttime sounds the animal makes are enough to make an unprepared greenhorn's blood curdle. The Devil's pitiful whining, choked roar, screeching and rumbling sounds are probably part of one of the most ghastly sounding vocal repertoires the animal world has ever produced.
The fact that the animals devour any corpses they can get hold of, even those of their own young -- skin, hair and bones included -- doesn't exactly make them endearing. They are even fond of chewing on skulls. Finally, their appearance makes these carrion-eaters seem somehow related to the antichrist: the deeply black fur, the pointed red ears that become bright red when the animal is agitated, and the gaping mouth with its 42 teeth, which the Tasmanian Devil can plunge into the flesh of its victims with a strength that approaches that of a leopard. Relative to its body weight, the Devil has the strongest bite of all mammals. To make matters worse, it exudes a stench that would put a skunk to shame.
An observer in the early 1900s described the Tasmanian Devil as a "case of ugliness going to the bone." The author described the animals' behavior with unveiled contempt: "They are very savage, and have frequent fights among themselves, while they slay other creatures for the mere wanton lust of slaughter." They were believed to tear their victims to pieces "in sheer ruthlessness."
It took a decades-long image campaign by ethologists to transform the Beelzebub into the island's ambassador. "They're such great little personalities," says biologist Jones enthusiastically. "They're sensitive, they're very intelligent and they're cheeky." Their screeching noises, the baring of teeth and fits of anger were eventually found to be part of a well-coordinated threatening behavior, with which the carrion-eaters, normally loners, manage to work together as a team to break up and distribute carcasses as large as cows -- without, as truly social animals would do, having to maintain a developed pecking order by engaging in exhausting fighting behavior.
Some biologists now believe that perhaps it is precisely the Tasmanian Devil's idiosyncrasies as a scruffy carnivore that make it so vulnerable to the cancer.
AP
Devil Facial Tumor Disease attacks the body like an acid bath.
The malignant cells are apparently passed from one animal to another through bites, during feeding or in a mating process, which isn't exactly a model of romantic tenderness. This theory is supported by the fact that so far most of the animals have fallen ill only after the age of three, that is, once they are sexually mature. In addition, the tumor always begins its destructive march in the mouth area. It begins in the form of small lesions on the gums or lips, which then grow into lumps and gaping wounds. The teeth fall out and the tumor grows even through the eyes. The Devil's face basically rots away while the animal is still alive. Within a few months the victims can no longer bite or swallow, and miserably die of starvation. No animal is resistant.
Baffled veterinarians
Veterinarians are perplexed by the horrendous growths produced by the condition, known as Devil Facial Tumor Disease. "We were baffled," says Stephen Pyecroft, a veterinarian. "We had 10 or 11 pathologists with 10 or 11 different opinions about what we were dealing with." Was it a virus? Cancer triggered by infection is not unknown in man. For example, the human papilloma virus, or HPV, can alter the genetic material of the cells in the cervix, causing them to degenerate. But in the case of Tasmanian Devils, scientists were unable to find any traces of viruses, neither in samples nor in cancer cells, that could have triggered the disease. Anne-Maree Pearse, a researcher, discovered, in a sensational study, that it is the cancer cells themselves that are infecting the animals. She determined that all of the tumor cells contain very similar genetic material. Each cell has only 13 chromosomes, or one chromosome less than healthy cells.
No virus does that.
Based on Pearse's research, it was clear that the deadly growths are not degenerated cells of the sick animal. Instead, they originate in a single cell that once mutated into a killer in one original animal -- essentially the originator of the epidemic. "I rushed out of my laboratory and skipped around the building," says Pearse, describing how excited she was to make the groundbreaking discovery.
But is this possible? Infectious cancer cells? Last August, researchers found that a type of tumor in dogs, transmitted during mating, also stems from a common ancestor, which at some point began to lead an independent existence as a pathogenic parasite. The discovery served to reconfirm Pearse's own work. However, these wild pathogens rarely kill their hosts, the dogs. The canine version of the cancer is relatively benign.
The race is on to keep the Tasmanian Devil alive. Every possible detail of the unusual tumor affliction is now being studied. How do the deadly cells circumvent the body's immune defenses? Can a test be developed to identify infected animals before the first lesion appears in the mouth? Could a vaccine be developed?
To prevent the Tasmanian Devil from becoming extinct before researchers have found answers to these and other questions, the Tasmanians have already embarked on a Noah's Ark project. At the beginning of the year they flew 47 healthy animals that had been in prolonged quarantine to the mainland. The group is dubbed the "insurance population." If the epidemic completely destroys the Tasmanian Devil, the rescued animals will be reintroduced to the Tasman Peninsula, from where scientists hope they will resettle their habitats.
But then they would likely face a new threat. The fox, introduced to the island by someone in the late 1990s, could have furtively taken over the Tasmanian Devil's niche by then.
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