Chicago is strategically using feral cats to deal with its huge rat problem

Rats remain a big problem for megacities — they're often fearless and intrusive, making their way into businesses and homes where they can spread diseases and cause destruction. Chicago has consistently ranked as the top US city with a rat problem, but it has a unique solution to this problem: strategically deployed feral cats.

Cats are a common sight in big cities around the world, often found hanging out in parks and on sidewalks. Many smaller businesses and factories welcome street cats due to their generally chill nature and ability to keep pests away, offering them shelter and food in return.

Chicago is embracing this symbiotic relationship between cats and humans by releasing a bunch of them in the city with the goal of driving away rats. Though cats aren't known for eating many rats, they do tend to go on brief killing sprees when they enter a new territory, which is enough to drive the rat populations away. The cat's continued presence in an area is enough to discourage the rats from returning while reducing or eliminating the need to use poison, which can harm other wildlife.

The cats are part of the Tree House Humane Society's Cats at Work program, which is an initiative to trap and neuter cats and then send them back out into the city — but with some protection and the assurance of a better life. The organization notes that in some cases, feral cats can't be reintroduced to their former colonies because of various issues, such as the colony potentially no longer existing.

In the case of these feral cats that aren't suited for placement in a shelter or home, they're put in the Cats at Work program and released in commercial or residential areas to provide rodent control. The businesses and people who benefit from the cats provide them with shelter, food, water, and attention.

Because these are feral cats, the program isn't introducing new felines onto the street, but rather relocating existing ones who are first vaccinated and neutered to help protect and limit the cat population. The cats are assigned a registered caretaker who is tasked with caring for the animal. More than 1,000 feral cats have been relocated to Chicago streets over the past several years.