“Wherever humans go, rats follow, forming shadow cities under our metropolises and hollows beneath our farmlands. They thrive in our squalor, making homes of our sewers, abandoned alleys, and neglected parks. They poison food, bite babies, undermine buildings, spread disease, decimate crop yields, and very occasionally eat people alive. A male and female left to their own devices for one year — the average lifespan of a city rat — can beget 15,000 descendants.” But that was all before someone came up with the idea of rat birth control. From The Guardian: Man v rat: could the long war soon be over?