I was greatly struck by a story, Rat attack: Mosman ready for rodent invasion, in today's Sydney Morning Herald. For those who do not know Sydney, Mosman is a posh, leafy suburb on the northern side of the Harbour.
The story is simple enough and is worth a read. By destroying the immediate natural environment around Mosman, the early European settlers drove out the native rat. Its place was taken by the European black rat, a species that has acquired a very bad reputation because of its role in great plagues such as the Black Death.
Now the plan is to trial the reintroduction of the native rat to Mosman in the hope that it will drive out the black rat. Sort of a good rat, bad rat story.