The Tasmanian Devil now only lives wild in Tasmania
and some smaller islands. It used to
live on the Mainland as well. They
probably became extinct on the mainland about 400 years ago. This was before European settlement.
Why did the Devil become Extinct on the Australian Mainland?
Of course we do not know because there are no written records from this time. One speculation is that they died out because of competition with Dingoes. This is possible, and the theory is supported (and suggested) by the absence of Dingos in Tasmania. However, the Dingo is a feral Dog, and there are feral Dogs in Tasmania, and have been since very soon after European settlement. The numbers of Devils built up after the systmatic attempts to exterminate this animal stopped, despite the large numbers of feral Dogs.
Another theory is that it was hunted to extinction by Humans. The trouble with this theory is that there were Humans in Tasmania. They would certainly have hunted Devils, but did not make them extinct. Another problem with the theory is that there were Humans in Australia for perhaps 50,000 years before the Devil became extinct.
The Thylacine became extinct on mainland Australia about 2000 years ago. Thylacines kill animals, but only eat some parts of them. The Devil would finish off the rest. The mainland extinction of the Thylacine would have removed one source of food, but Devils survived the extinction of the Thylacine on Tasmania and were building up in numbers, depite the absence of Thylacines and the presence of feral Dogs until they were attacked by disease.
My own theory of the extinction of the mainland population of Devils is that it was due to a combination of factors, but mainly due to the hunting of them by Humans using Dogs. The Dingo was introduced as a domestic Dog, perhaps 3500 years ago. The Humans who were hunting made use of the semi-domesticated Dingo. Although a Devil might be able to hide from people, Dogs can find them by smell. The extremely strong bite of the Devil is certainly some protection from Dogs, but much less so from the spears of the people.
Tasmanian Devil
By Aenneken [CC-BY-2.0 (www.creativecommons.org/licenses/by/2.0)], via Wikimedia Commons
Largest
Carnivorous Marsupial
The Tasmanian Devil is the biggest Marsupial Carnivore. This also
means that it is the biggest carnivorous Mammal native to Australia still
in Existence. When Europeans first came
to Australia,
there was one Carnivorous Marsupial bigger.
This was the Thylacine or Tasmanian Tiger.
Of course there are bigger
Carnivores in Australia. The biggest one is the badly named Salt Water
Crocodile.
Scavenger
Although the devil will certainly
hunt, it is largely a scavenger. It does
an important job on farms, eating any dead animals. The very strong jaws allow it to eat all
parts of the animal including the bones.
If a large animal dies there canbe a number of these scavengers round the carcase making very alarming noises.
Their natural prey includes
Wallabies like the Tasmanian Pademelon. They will eat whatever animal they can catch or find like reptiles, birds,amphibians, insects and things washed up on the beach.
Endangered
For over a hundred years this
animal, together with the Thylacine was shot, trapped and poisoned. The Thylacine is now probably extinct, and it
appeared that the Devil was heading the same way. In 1941 it was given total protection under
the law.
The numbers steadily increased until
the 1990’s. Then they were struck by a
devastating disease.
Devil
Facial Tumour Disease
This fatal disease causes cancers
on the animal’s mouth, face, neck and sometimes other parts of the body. Where the Devil population is high, as much
as 90 percent of these animals are dying.
In lower population density areas, the mortality rate is more like 50
percent. This terrible disease seems to be spread by physical contact.
The numbers of this iconic animal
are decreasing.
Foxes have got to Tasmania. So far they are only present at low densities, but if they are allowed to increase
their effect on the Devils is unknown, but potentially disastrous. On the mainland they have contributed to the
extinction of many species.
Knowing how stupid a few Humans can be it is reasonable to guess that Foxes had been brought to Tasmania several times before, but failed to become established. The thing that is different now is the Devil Facial Tumour Disease. It is quite possible the the Devils were controlling the Foxes, but cannot do it now because there are less Devils.
Cats are also starting to build up in numbers now there are less Devils.
Threatened
Because of the Devil Facial Tumor Disease and the past actions of Humans, The Tasmanian Devil is threatened with extinction. It has been suggested that they will be extinct in the wild in 20-30 years. There are things that we can do to save them, and some of these things are being done.
Research
Research is being carried out into the disease. Potentially, understanding this terrible disease could not only benefit Devils, but could also add to our knowledge of cancer in general and possibly contribute to pointing the way to cures of Human cancers.
Captive Breeding
The Zoos of the Autralasian Region are co-orperating on a captive breeding program in zoos on the mailand of Australia, well away from infected Devils.
Monato Zoo had 12 of the 36 Devils brought from Tasmania and is successfully breeding them.
Tasmanian Devils are mainly nocturnal.
This one thought it was invisible in the darkness of a log'
but it was at the Adelaide Zoo and a sharp eyed child spotted it.
The night shot setting of the camera showed a lot more than we could see.

Could Devils Survive on the Mainland of Australia?
Since we do not really know why they became extinct, we can only guess the answer to this question. If it was competition with Dingos, then since there are few Dingos left in the wild, Dingos would not stop their re-establishment. Humans are still hunters, but this can be controlled by law and custom.
There is some uncertainty about the ability of Devils to compete with Foxes, but is seems most likely that they could.
Fox Mange could be a problem to the Devils just as it is a problem for Wombats.
My guess is that The Devils are capable of surviving in the wild in some habitats on the mainland of Australia. The Zoo project could be extended in stages with Devils being released in very large fenced areas. The first of these areas would probably be cleared of Feral predators, but later ones could have some left in to see if the Devils can compete.
This would have to be a long term project.