The Fox in Australia
Humans outfoxed
"when animals of this class (marsupials) suddenly find themselves placed in competition with such advanced forms as the Fox, the Cat, and the Rabbit - types far ahead of them on the evolutionary scale - it is ...inevitable that they should go down before the invader" 1923, Albert Le Souef, curator of Taronga Park Zoo
A great example of importance of biodiversity can be seen in the respective fate of red foxes introduced to Tasmania versus those introduced to mainland Australia. The fox was first introduced to Tasmania in 1864. It was probably introduced again, or stowed away on ships, numerous times over the next hundred years, but it never seemed to take hold. Signs of continued deliberate or accidental introduction were seen in 1972 when a fox was caught in a rabbit trap. More signs were seen in 1998 when a fox stowed away in a container from Melbourne. In 2002, Tasmanians started reporting sighting in such numbers that a breeding community might have taken hold.
Although the fox has always struggled in Tasmania, it has thrived on the mainland. It was introduced for hunting in 1855. It soon decimated marsupial populations and also attacked lambs on sheep farms. As a result, mainland Australia has lost 17 marsupials in the last 200 years and 59 are at risk of extinction. Tasmania has only lost the Tasmanian Tiger.
Humans have tried to reduce fox numbers with a combination of shooting, trapping, baiting, and fencing but they have been out-foxed. Despite all the modern technology, they haven't even been able to eliminate the fox from Victoria's Port Phillip Island, let alone the 7.6 million square kilometers of Australia. Much like the 1,833 km fence built to keep rabbits out of Western Australia, the control regimes are noble in spirit but silly in logic and a waste of money.
The fox has never been able to replicate its success in Tasmania because the Devil has proved too much of a match for it. A 10kg Devil can exert the biting pressure of a 40kg dog. A 3-10kg fox just can't compete in a one on one battle. According to Stephen Wroe, a Palaeontologist who has analysed how they would go in a one-on-one battle,
"In one-to-one situations, our results suggest that the devil would easily prevail and even give dingoes [wild dogs] a run for their money."
The fox's weakness in comparison to the Devil is a significant liability. Devils follow other predators around and chase them off their kills. Furthermore, because the fox is a placental mammal, it builds dens for its young. These dens can easily be sniffed out by Devils, who can devour the fox pups irrespective of whether the mother is defending them or not.
The Devil existed on mainland Australia until a few centuries ago. Because they were quite easy to track, they might have been hunted to extinction by nomadic humans. Alternatively, because they hide in logs, they may have been killed off by humans using fire in hunting. (The Tasmanian hunter gatherers didn’t use fire in hunting.)
The elimination of the Devil was quite beneficial for the Dingo, another introduced species. With Devil numbers low, and Tigers eradicated or close to it, the Dingo entered the mainland ecosystems with only humans above them. Fortunately for the ecosystem, the Dingo was not a great hunter of marsupials and quickly found a balance with humans and with native prey.
Potentially, the Dingo could serve a role of fox controller on the mainland. Professor Chris Johnson, from James Cook University, has found that in places where Dingoes are rare or absent, and foxes and cats are abundant, 50 per cent of ground-living mammals have vanished. Where Dingoes remain abundant, the rate of local disappearance is 10 per cent or less.
| Wednesday, 03 October 2007 |
| By Chris Johnson |
Although it could provide some help in controlling fox numbers, the Dingo is not as effective as the Devil. The Dingo is a superior hunter so relies more on catching its own food rather than chasing foxes off their years. Furthermore, even though Dingoes reach weights of up to 20kg, they still don't have bites as powerful as Devils. Taking on fox is more of a risk for a Dingo than it is for the Devil.
In order to control foxes and protect mainland marsupials, Professor Chris Johnson has argued in favour of reintroducing Dingoes, Quolls and the Devils to the various mainland ecosystems that humans have eradicated them from. Professor Johnson has stressed that native predator communities need to be rebuilt because they have the ability to remain in balance with native prey. As native predators replace the feral predators, or reduce their numbers, native prey is able to rebound.
Although there is a strong scientific argument for reintroducing the Devil to control the fox, there is also strong ideological opposition. Contemporary left-wing ideology involves trying to return Australia to how it was in 1788. While Devils might have been on the mainland in 1388, 1788 is the benchmark year.
The problem with the 1788 ideology is that unless 1,000,000 Australians volunteer to become nomadic hunter gatherers, any 1788 ecosystem will lack the top predator. Furthermore, there has been 2020 years of evolution since 1788. It is not possible to recreate the past. As long as the 1788 ideology prevails, humans will continue to find that the cunning of a fox is too much for them to deal with.
