I’m currently reading Hero of the Empire by Candice Millard, a book about Winston Churchill’s participation in the Second Boer War in South Africa. After he escapes from a POW prison, he is briefly hidden by British sympathisers in the coal mine of the Transvaal and Delagoa Bay Colliery. Millard writes that the man who oversaw the mine, John Howard, had purposefully introduced albino rats into the depths.

“Churchill had not spent the night alone after all. Several years earlier, Howard had introduced into the mine a species of white rat that was, in Churchill’s words, ‘an excellent scavenger.’ The rats had thrived in the dark recesses of the mine and had quickly added to their numbers until there were now swarms of them, clever, quick and able to make a living off anything they could find, including Churchill’s candle.”

Later, he is led through the mine by two Scottish workers and the lantern light provides a better glimpse:

“Mostly what they saw were rats. Fortunately, Churchill had ‘no horror of rats’ and thought that the ones scurrying around the mines were ‘rather nice little beasts.’ He admired their sleek white fur and their dark eyes. His guides, however, assured him that if he could see the rats in natural light, he would find that their eyes were in fact bright pink. They were albinos, and so had even worse eyesight than most rats as well as a unique sensitivity to light, all of which made them, unlike Churchill, perfectly suited to life in the mine.”

Millard describes Churchill’s annoyance as the rats harass him in his sleep and steal his candles, but never mentions their actual purpose in the mines. Does anyone know why they would have been added in the first place?