Australia Fighting Rats —With Rats

In the what-could-possibly-go-wrong department: Australia hopes to rid the Sydney Harbour area of black rats by introducing a different species of rat into the area, reports Reuters. The black rats are non-native invaders that probably arrived by ship 200 or so years ago, and they're a huge nuisance near the harbour because they love the local plants, climb trees to eat birds' eggs, and like to nest in humans' houses.

Solution: Bring in the native Australian bush rat, which is said to have much nicer manners on all fronts. Authorities began the process yesterday by trapping and removing 40 black rats and setting free the same number of bush rats in the area. "We know from basic theory that if you have an intact native fauna then invaders can't get into those areas," explains a University of Sydney professor. "So we thought maybe we can use the same logic by taking black rats out and putting bush rats in." (More Australia stories.)