New York Is Sterilizing Its Rats. Here's How

No one knows exactly how many rodents reside in New York, but there may be as many rats as humans by some estimates. That’d be 32 million scurrying legs. Rats are remarkably fertile, sometimes birthing 12 pups per litter and as many as seven litters a year. That’s why the Metropolitan Transportation Authority has started a pilot program to sterilize females. It’s teaming with Flagstaff (Ariz.)-based SenesTech, a company that invented ContraPest, a product that, when consumed orally by rats, accelerates egg loss and can cause infertility in days.

New York’s rat extermination proposals in the past have included everything from the deployment of World War I-era poison gas to a hunting spree led by rifle-bearing citizens. (The gas was used with some success on Rikers Island, now home to one of the city’s jails; the hunting party apparently was called off at the last minute.) This is the MTA’s first effort to target the rodents’ reproductive organs.