In 1872, a Jamaican planter imported nine mongooses to kill rats in his sugarcane fields; the predators then turned on native birds and reptiles

Jamaica’s sugar profits were being nibbled away by rats, so one planter imported a small predator to fix the problem. And it worked, for a while. Then everything else started disappearing too. According to a 2023 study by historian Matthew Holmes, published in the British Journal for the History of Science, this 19th-century experiment is one of the clearest early warnings about what happens when humans move a predator to a place it’s never lived.

A rat problem that seemed easy to fix