That's the question isn't it?......Nobody knows exactly but there are plenty of theories floating around out there and I'm going to explore a few of them here. Now these are my theories, enthusiasts and even professionals although all off the record and naturally I am not going to reveal who said what. So remember everything below are just theories (more like possiblities) not fact, maybe you have a theory of your own.

Scientist are working hard to find out exacting what the diseases is at this stage rather than what has caused it. This is a normal procedure in medical science. If you can determine what the disease is then it is easier to track down the cause - which I guess really makes sense.

The number one suspect in the cause of the DFTD disease is HUMANS. Yes the human race and our actions in the past and today
have probably lead to this devastating disease.

They say that top end predators/carnivores often reflect the health of the ecosystem of the area. The Tasmanian Devil since the extintion of the Thylacine has become Tasmania's top end predator and with it in such crises with this disease, should we be looking at the overall health of Tasmania's Ecosystem?

Tasmania is only a small isolated island and it has always had a reputation as being an oasis with clean water and air, magnificient forests, rare and plentiful wildlife and little evidence of disease. Are we poisoning and destroying the natural balance? Could this Devil disease eventually pass onto other species and finally livestock?

The use of poisons in Tasmania is widespread and has to be investigated as a possible contributor to DFTD. Farm chemicals and diesel fuel have been used in rural areas for many decades as well as the widespread use of 1080 poison.

The spread of 1080 poison to kill wildlife for purely economic reasons is not new to Tasmania, however with increased clear fell logging being conducted throughout Tasmania particularly since 1996 and new Niten gum tree plantations being established, 1080 is being used more than ever.

1080 is used to kill wildlife such as wallabies and possums to prevent them from grazing on new seedlings that have been planted. Carrots laced with chemical toxin sodium monofluoroacetate (1080) are scattered in the area. Around 100 000 macropods a year a killed by Forestry Tasmania, GUNNS and private property owners. Of course the poison goes through the food chain with not only Tasmanian Devils consuming the poisoned carcasses also the endangered quoll and Wedge-tailed Eagle feast upon them. It is reported that the baits laid are not a high enough dose to kill these carnivores.

Research however shows that the poison is present in higher concentrations in the stomach and other organs. If these are ingested the animal could get secondary poisoning. I could be mistaken although I don't believe so as I have witnessed it, Devils consume everything, all organs, bones and fur, so okay it may not kill them but I I believe it must be making them sick and could it be affecting their offspring. The possiblity that 1080 could contribute to the disease could be possible.

At the Boomajaril Property in the North West of Tasmania in 2003, there were 12 Devils and 2 Quolls who were regular visitors to the property and interacting with the residents. A major 1080 carrot drop in the neighbouring area with new plantations commenced in April 2004. Within two days all the Devils (except one) and Quolls were gone, never to be seen again. Could it just be a co-incidence. Could they have all just moved on at the same time? Later years proved that was unlikely, it was more likely they had all died.

Also as part of the forestry/Gunns maintainance of their new plantation is the control of pests. Potentially lethal Agicultural pesticides are aerial sprayed over the crops, these pesticides have been linked to diseases in animals affecting the liver, kidneys and heart. It also causes changes in blood hormone levels. Most of these chemicals are slow to breakdown in water, so pollution of waterways close to aerial spraying is possible and can be easily ingested or bathed in.

Another concern is the Rabbit Calicivirus which was introduced in 1996 in the latest effort to control the plague of introduced rabbits. The problem here of course is that Devils eat dead rabbits and is probably one of their main food sources.

Land clearance whether for farming or forest plantation must be having a tremendous impact on the Tasmanian Devil. Not only are their home ranges destroyed, as well as Dens that have been in use sometimes up to 100 years their food source is also destroyed with all macropods their main food source, killed off providing a poison ridden one off feast, then months and months of no food. Death from starvation, particularly for young devils is likely. And you need to take into account the amount of stress it must be causing the animals particularly if overcrowding occurs as they move to sheltered bush areas. This must make them more susceptable to disease.

Land clearance also increases the risk of Devils being cut off from other populations. This could result in them inbreeding with the result being a lack of genetic diversity and could trigger the action of a dormant retrovirus. Other drops in Devils populations in the past from trappings and killing of Devils when they were thought to be a threat to livestock could have also experienced this problem of inbreeding and maybe something in the environment now has triggered the disease.

It could also be a naturally occuring disease to control the Devil Population. If that is the case then the Devil is most definately marked for extinction.

There is one year that stands out throughout this article that is interesting. 1996.

• In 1996 the Devil Disease was detected.
  
• In 1996 major clear fell logging of forests was underway, laying 1080 poisons and aeral spraying of poisons.
  
  In 1996 the Rabbit Calicivirus was introduced to Tasmania.

Not saying there is a connection, but it is certainly interesting.