Steve

Humans first settled in Australia perhaps 40,000-50,000 years ago. There is no evidence that these first Humans brought animals with them. Later Humans definitely did. Australia was not completely isolated from the rest of the world and there were several groups of seafaring peoples from Asia and the Pacific who came here. One animal that became established in Australia was the Dingo. This was apparently brought here as a domestic Dog at least 3,500 years ago.

Another animal that was apparently brought here was the Cat, including the domestic Cat, Felis catus. This may have been brought here as long ago as 10,000 years. It is probable that it came here quite a few times after that. It failed to survive in Australia until after European Settlement in 1788.

Why Cats Died Out

The early introductions of Cats were into an ecosystem including Thylacines as the top land predator and Tasmanian Devils as a major Carrion eater and hunter when necessary.

With later introductions, the Cats had to contend with the Dingo.

Why Cats did not Die Out

When Europeans came here, they deliberately set out to kill Dingos. The Thylacines and Devils of the mainland had already disappeared. The first British settlers kept Cats as pets, and for rodent control.

At first Cats were able to spread out from the settlements, but later were deliberately introduced into the Australian Bush.

Cat Problem

In most ecosystems round the world, Cats, Felis Catus, and Foxes, Vulpes vulpes, are not a major problem. Generally they are not the Top predator of an ecosystem. In Australia this used to be the case, but the top predators have been killed off, either deliberately or by unplanned consequences of Human actions.

Three Groups of Cat

On Australia, Cats can be divided into three groups.

Pet Cats.

Stray Cats.

Feral Cats.

The Feral Cat population is now well established and does not depend on regular recruitment from the other two groups although this does occur from time to time.

Pet Cats need to be treated responsibly. They are lovely pets and should be treated accordingly. This includes desexing all Cats unless there is a deliberate plan to breed. Cat breeders then need to only allow their Kittens to go to good homes.

Personally I am against the selling of Kittens from Pet shops. Our local Vet often gets Kittens dumped at her place, or given to her more openly. She treats them very well and sells them including desexing in the price.

Once pet Cats are properly controlled, the local authorities can deal with stray Cats more easily. This will help prevent the sporadic recruitment of more Cats to the wild population.

Feral Cats

Although it is necessary to deal with Pet and Stray Cats, this will not solve the Feral Cat problem.

A Diabolical Solution

Perhaps the ideal solution would be to re-introduce Thylacines and Devils to the mainland. Unfortunately, since the thylacine is probably extinct, this is not possible at present. Attempts are being made to bring back the Thylacine, but this is a long term project.

However, the Tasmanian Devil is still in existence. Until comparatively recently they were widespread on the mainland. In Tasmania they appear to be controlling the Cats. There is no evidence that Cats are being killed in Tasmania by the Devils. Although Devils will certainly eat Cats, they also eat any dead animal they find. Cats would appear to be able to evade Devils better than they can evade Dogs. Neither Dogs nor Devils climb trees like Cats, and Dogs can run much faster than Devils.

The Tasmanian Devil can only run at about 13 Kilometres (8 miles) an hour, and it can only keep up this speed for a short time. This is much slower than a Cat can run.

The mechanism of control appears to be competition for food. A common Devil tactic to get a meal is to follow a hunting Quoll, and after the Quoll kills something to chase the Quoll away and eat their kill. The Devils seem to do the same to Cats, but Cats take longer to kill an animal than Quolls. The Cats are controlled without being killed.

The obvious thing would be to have a trial re-introduction of the Devil. To do this it would be necessary to fence a large area. Devils can probably compete with Foxes as well as Cats, especially if there are plenty of Devils.

The Devils would need to be taken from a population not affected by Devil Facial Tumour Disease.

Sources

http://www.environment.gov.au/biodiversity/invasive/publications/cat/pubs/cat.pdf

http://www.convictcreations.com/animals/feralcat.htm

http://www.sciencealert.com.au/opinions/20070310-16405.html

http://www.environment.nsw.gov.au/pestsweeds/FeralCats.htm