New York City's mayor, Eric Adams, has opened up a new front of his war on rats. Mr Adams, who already made headlines for appointing a "rat czar" last year, has escalated his campaign against the city's ubiquitous rodents. Last week, he announced the creation of the "Rat Pack", which he billed as an "elite squad of anti-rat activists" who will take the fight to the enemy.
While it's easy to dismiss these efforts as political posturing -- rats don't vote, after all -- Mr Adams is on to something. Unlike past campaigns against the wily rodents, he is embracing some common-sense tactics that, while not as showy as past anti-rat tactics, may deliver some enduring results.
The first rats likely reached New York City sometime in the colonial era. These immigrants -- a subspecies known as Rattus rattus, the black or ship rat -- found streets paved with gold: the refuse dumped on city corners, back lots, and garbage piles. The newcomers thrived for a few decades, but they were quickly displaced by their far more adaptable cousins: Rattus norvegicus, better known as the brown rat.
The brown rat was astonishingly omnivorous, readily consuming anything that humans ate -- and some other things, too. This became apparent when a cholera outbreak ravaged New York City in 1849. As bodies lay in the streets, beleaguered city officials dumped the corpses into an open grave on Randall's Island. Day after day, thousands of rats in Manhattan, catching wind of a once-in-a-lifetime, all-you-can-eat buffet, swam across the East River to batten on the corpses, leaving behind little but bones.
Despite this gruesome episode, the city didn't really bother to do much about rats at this time, largely because it struggled to regulate far larger, more dangerous animals: packs of wild dogs and feral cats, some of them rabid; and a remarkable number of pigs that wandered the streets, scavenging for food. As a consequence, rat control was a private matter that relied largely on terriers trained to kill the rodents.
By the 1830s, these dogs and their quarry became the basis of a popular spectator sport. In the poorest parts of Manhattan, children would catch rats and sell them to gambling parlours. The proprietors would then release them into pint-sized amphitheatres to face off against terriers. Everyone had their favourite dog, and patrons would bet on how many rats their canine gladiator could kill in a set period of time. Fast forward 50 years and city officials had banned "rat-baiting", but the business of killing rats had grown into an actual full-time profession. There was no shortage of work. In 1888, one newspaper counted a total of ten rat catchers for a city of nearly two million people -- enough to clean up a single building, perhaps, but not much more.
By the early 20th century, general acceptance of the germ theory of disease -- and a widespread recognition that rats could carry pathogens, including bubonic plague -- led public health officials to declare war on rats. This went hand in hand with a larger effort to create and maintain a more beautiful, clean, sanitary city.
So began a grim quest to find the best way to exterminate them. Conventional methods included the use of dogs, obviously, as well as ferrets, and even snakes and the occasional mongoose. Traps came in all shapes and sizes: cages, barrels and other contrivances. Yet as public health officials acknowledged, rats could be remarkably picky eaters when it came to bait. "The rat is more or less an epicure," advised one official. "He should be given food which he is not in the habit of getting."
Besides being picky eaters, rats displayed Houdini-like behaviour when it came to traps, escaping unharmed with the bait. In response, the authorities increasingly resorted to poisons: old standbys like barium carbonate, arsenic, and strychnine as well as newfangled toxins like red squill, derived from the bulbs of a subtropical lily plant. The wily rats quickly learned to avoid many of these poisons (or in some cases, developed immunity to them). Undeterred, New York and other cities launched a series of grim experiments designed to test various toxins. In 1930, the New York Times reported how members of the Sanitation Department had donned masks and deployed chemical weapons used in World War I against the rats of Rikers Island, pumping burrows full of poison gas.
The assault failed, as did other efforts in the succeeding decades. In 1948, for example, a "council of war" made up of city officials and known as the "Technical Committee on Rat Extermination" sowed poison food through the city. They even deployed bacterial cultures sold by the Pasteur Institute, hoping to sow an epidemic among the rodents. A couple decades later, health officials unleashed a new generation of anticoagulant poisons.
Invariably, these military-style campaigns produced a fleeting reduction in the rat population, with the number of brown rats rebounding a year or two later. This was inevitable. On average, a female brown rat gave birth to three litters of ten young every year. "Under conditions ideally favourable," one public health official observed, "it has been computed that one pair of rats will in five years, providing all can live so long, increase to 940,369,969,152" -- just short of a trillion.
Obviously, not all members of each litter survived to adulthood in real-world conditions. But enough did to guarantee that any extermination campaign collided with the reproductive prowess of the brown rat. Indeed, it was around this time that a growing number of sceptics began to question the single-minded focus on eradication.
Murry Raphael, director of the city's Bureau of Pest Control, dutifully carried out the conventional war against the rodents in the 1960s. In 1964, though, he cut straight to the underlying issue in an interview with a journalist. "The rat problem's really a human problem," he noted. "You could poison all over the place, and still, if you had a dirty apartment, you'd have rats…If you deprive the rat of food and water, then he'll have to go somewhere else."
Wise words. But much of the effort in subsequent years continued to focus on extermination, which tended to play better with voters than preachy pleas to clean up food scraps. Nonetheless, mayors in this century seem to have grasped this fundamental truth: while you can't poison your way out of the problem, you can limit rats' access to food and, by extension, curb their population.
Though Mayor Adams found himself mocked mercilessly last year when he announced "wheelie bins" to better contain the city's trash, this is precisely the kind of low-tech solution that will ultimately prove more consequential than the mad-scientist schemes that an earlier generation of anti-rat warriors embraced. The mayor's focus on education, which focuses on prevention, is also more likely to have more enduring effects.
Will this lead to a rat-free New York City? No. Brown rats are here to stay because they're what Robert Sullivan has described as a "mirror species", one whose fortunes rise and fall with our own. And that insight, more than traps and poisons, is key to managing our mutual co-existence. ©2024 Bloomberg L.P.
Stephen Mihm, a professor of history at the University of Georgia, is coauthor of 'Crisis Economics: A Crash Course in the Future of Finance'.