Hanoi's Rat Bounty Blunder

In 1902, French authorities in Hanoi, Vietnam, concerned about a large rat population, offered a bounty for rat tails as proof. Thousands of tails were submitted daily, but the rat issue worsened. They discovered that hunters were breeding rats rather than hunting them for their tails. The rat population grew to the point where a bubonic plague outbreak in 1906 killed 263 locals.

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