There’s an oft-quoted passage in Terry Pratchett’s Soul Music illustrating the mentality of Ankh-Morpork and the practical genius (or extremely efficient common sense, if you will) of Lord Vetinari:
“Shortly before the Patrician came to power there was a terrible plague of rats. The city council countered it by offering twenty pence for every rat tail. This did, for a week or two, reduce the number of rats – and then people were suddenly queuing up with tails, the city treasury was being drained, and no one seemed to be doing much work. And there still seemed to be a lot of rats around. Lord Vetinari had listened carefully while the problem was explained, and had solved the thing with one memorable phrase which said a lot about him, about the folly of bounty offers, and about the natural instinct of Ankh-Morporkians in any situation involving money: ‘Tax the rat farms.’”
So this actually happened (minus the taxing) in Vietnam under French colonial rule, aka French Indochina, around 1900. There was an outbreak of the bubonic plague, brought by rats which hopped on the new colonial trade routes along with all the people, and then shacked up in Hanoi’s brand new sewers – ironically built to improve the city’s hygiene. They found no predators there but plenty of food, so they multiplied like an invasive species. And they carried the plague, to both cities. (Hanoi, in typical colonial fashion, was separated to the “European city”, spacious and luxurious, and the Vietnamese one, with all the overcrowding you expect. But that was only topside: the sewer system ran through the whole city.)
So rats were immediately identified as a lethal threat, and locals were hired for the extremely unpleasant and dangerous task of going through the sewers and killing them. When that wasn’t enough (rats multiply… a lot), someone had a bright idea:
“To fight the infestation citywide, the colonial administration added vigilantes to its team of professional killers. Appealing to both civic duty and to the pocketbook, a one-cent bounty was paid for each rat tail brought to the authorities (it was decided that the handing in of an entire rat corpse would create too much of a burden for the already taxed municipal health authorities). Unfortunately, this scheme backfired. Despite initial apparent success, the authorities soon discovered that the best laid plans of mice and men often go awry. As soon the municipal administrators publicized the reward program, Vietnamese residents began to bring in thousands of tails. While many desk-bound administrators delighted in the numbers of apparently eliminated rats, more alert officials in the field began to notice a disturbing development. There were frequent sightings of rats without tails going about their business in the city streets. After some perplexity, the authorities realized that less-than-honest but quite resourceful characters were catching rats, but merely cutting off the tails and letting the still-living pests go free (perhaps to breed and produce more valuable tails).
Later, things became even more serious as health inspectors discovered a disturbing development in the suburbs of Hanoi. These officials found that more enterprising but equally deceptive individuals were actually raising rats to collect the bounty. One can only imagine the frustration of the municipal authorities, who realized that their best efforts at dératisation had actually increased the rodent population by indirectly encouraging rat-farming. Evidently, this was not what the French had in mind when they encouraged capitalist development and the entrepreneurial spirit in Vietnam. Faced with such fraudulent schemes, the colonial regime scrapped the rat bounty program. In the end, the campaign failed miserably.”
– Michael G. Vann, “Of Rats, Rice, and Race: The Great Hanoi Rat Massacre, an Episode in French Colonial History” (French Colonial History, Vol. 4, 2003). See also Vann’s graphic history, illustrated by Liz Clarke, The Great Hanoi Rat Hunt: Empire, Disease, and Modernity in French Colonial Vietnam (Oxford University Press, 2018), and his interview on the Infectious Historians Podcast Episode 28: “The Great Hanoi Rat Hunt”.
What I find fascinating is that, as far as I can tell, the article I cited above is the one which introduced English speaking audiences to that incident, and it was written 9 years after Soul Music. So in all likelihood,Terry Pratchett didn’t know about it. (At least, that’s my best guess.) But he may have know similar ones, from fact or fiction.
- There’s an anecdote that in Delhi under British colonial rule, the government offered a bounty for dead cobras. This led directly to cobra-breeding, and their population dramatically increased. [x]
- I saw someone claim that the exact same thing with the rat tails happened in early 20th century Brazil, with the efforts of Oswaldo Cruz to battle the bubonic plague. I don’t know if it checks out or if it’s a myth. [x]
- There was apparently an old joke about Ioannis Metaxas, the Greek fascist dictator (late 1930s), that he went to Bulgaria on a state visit, and saw forests everywhere and was very impressed, so he asked the King of Bulgaria “how do you do it? how do you get so many forests? we hardly have any!”. The King said “easy, I shot all the goats.” The dictator comes back to Greece and proclaims a bounty for goatheads. Immediately everyone starts breeding goats. [x]
- From the Autobiography of Mark Twain: “Once in Hartford the flies were so numerous for a time, and so troublesome, that Mrs. Clemens conceived the idea of paying George a bounty on all the flies he might kill. The children saw an opportunity here for the acquisition of sudden wealth. … Any Government could have told her that the best way to increase wolves in America, rabbits in Australia, and snakes in India, is to pay a bounty on their scalps. Then every patriot goes to raising them.” [x]
And there’s probably more. What I didn’t find in any of them was taxing the farms. That’s probably all Pratchett.