After Chicago’s stores and restaurants shut down in March, Rebecca Fyffe, the director of research at a pest-control company, went on one of her usual evening “rat safaris.” Her employer, Landmark Pest Management, services many of the city’s high-end, Michelin-rated restaurants, which had been forced to close hastily, dumping piles of produce. Beside a dumpster near one such restaurant, Fyffe came across cases of past-prime avocados. “I saw this box of avocados just teeming with rats,” she says. As the city’s humans retreated home to avoid the coronavirus, its rats got “one big, final buffet.”
Then, however, came the famine. Restaurants remained closed, and nearby rat colonies started to starve. In restaurant-heavy neighborhoods, Fyffe began seeing more rats with wounds from fighting over food. She started finding more of the creatures in her traps too, probably because the bait had become a lot more enticing. Then, finally, the rat population in some areas started to drop. In the month from April 20 to May 20, her team trapped 19 rats outside a closed Chicago restaurant. In the two weeks following May 20, they trapped only two.
The coronavirus pandemic has upended human life in cities, which means it has also upended the habitat of city rats. In their millennia-long coexistence with humans, rats have acclimated to our changing ways of life and they are acclimating again to pandemic-stricken cities. “This is sort of a natural experiment,” says Maureen Murray, a wildlife-disease ecologist at the Lincoln Park Zoo in Chicago. Cities are now slowly reopening, and rats will adapt again—as they always have.