He lost by more than a whisker. Last month, you could almost hear squeaky sighs of relief as Romans rejected mayoral candidate Antonio Razzi and his plan to eradicate the Eternal City’s 6 million rats by importing half a million feral cats from Asia. Razzi envisioned a city filled with stray felines — cared for by Rome’s famed gattare, or “cat ladies” — but voters had other plans.
Vermin aren’t just a Roman problem, of course. Somerville, Massachusetts, is turning to big data to solve its infestation issues, and some islands are scattering poison from helicopters to try to kill off nonnative rodents. Complaints in Chicago are at a five-year high, and Boston, Washington, D.C. and New York City have all seen an upswing. The pests have spread to every landmass on Earth, save for the North and South Poles, chewing their way through wooden structures, devouring food and threatening to spread diseases. Cities that have experienced a surge in the furry menaces are turning to both high- and low-tech solutions, as well as studying the tactics used by the world’s few success stories in eradicating the four-legged pests.
Pet rats are illegal in Alberta, not because officials are worried about escapees but because the province’s rat-free status depends on citizens reporting whenever they see one.
Paris has so many rats that a local paper ran an April Fool’s Day story two years ago detailing a plan to wipe out the city’s rodent population — that’s how far-fetched the notion of a ratless city seems. But the beasts cause big problems for the City of Light. Thriving off the waters of the Seine, rats send picnickers scurrying from fancy gardens, damage buildings and leave behind feces — not to mention infecting hundreds of Parisians each year with leptospirosis, a bacterial infection spread by animal urine.
In contrast, the Canadian province of Alberta saw just three rat infestations last year — a big year, says provincial rat and pest specialist Phil Merrill. Alberta has been considered “rat-free” for decades, and while it often consults with other provinces and cities looking to follow in its verminless footsteps, “we really don’t know how to handle rats all that well,” Merrill admits. Why? Because they’ve never had to. Alberta jumped on the rat problem early, taking steps to keep the rodents out in the 1950s while infestations were ocurring elsewhere.
Geographically, Alberta is well placed to keep the rodents at bay. The landlocked province can’t harbor rat-filled ships, and with British Columbia’s sparsely populated mountains to the west, Montana’s relatively rat-free plains to the south and the frozen Northwest Territories to the north, Alberta’s only rat-risky border is with Saskatchewan. They’ve marked out an 18-mile border zone there, and Merrill estimates pest specialists spend about four weeks a year addressing potential problems to keep the vermin out. The 4.1-million-strong province also wages a war of perception: Pet rats are illegal there, not because officials are worried about escapees but because Alberta’s rat-free status depends on citizens reporting whenever they see one. “If new people coming into Alberta saw rats in pet stores, they’d say, ‘Alberta’s not rat-free,’ ” Merrill explains.
Data reporting is also key to cities like Somerville, which encouraged citizens to call 311 whenever they saw a rat and managed to reduce reported sightings by roughly two-thirds in one year. This big data approach has seen good results, but it can encourage non-holistic solutions, says Dawn Day Biehler, author of Pests in the City. She worries that focusing on sightings means cities miss bigger problems: “We’re a throwaway culture, which creates these large streams of garbage in our cities, and I don’t think our sanitation systems are up to the challenge.” Biehler believes a combination of less waste and better trash-removal systems is needed.
Meanwhile, Hawadax Island — formerly known as Rat Island — has used aerial drops of poison pellets to eradicate rats, ushering in a safe environment for local birds. But that tactic doesn’t always work: Henderson Island, in the South Pacific, tried dropping poison in 2011 only to see rat populations rebound, likely due to heavy rainfall that boosted food supplies.