The Jacob J. Javits Center recently said its using feral cats to control its rat population. The Center's four cats, whose names are Sylvester, Alfreda, Mama Cat and Ginger, according to the Daily News, came from the Feral Cat Initiative under the Mayor's Alliance for NYC's Animals.  

But rodent control is not the program's main objective, said Michael Phillips, the outreach coordinator.

"To have as few cats on the street as possible, that is our mission," Phillips said. "However, one of the collateral benefits is non-toxic rodent control."

About 6,000 people in New York City have been trained to trap, neuter, and vaccinate cats for rabies. Phillips said the group does not put feral cats on the streets, but sometimes their existing colonies become unsafe for them. That's when they'll relocate cats to a new colony, like the Javits Center two years ago.

But Phillips said you have to provide them with daily shelter and food. Otherwise, the cats will leave and the rats will come back. 

"Cats are very opportunistic. They'd go looking for a meal here, there, everywhere," said Phillips. "But by caring for them, the breeding female rats, they're not going to have little baby rats in the middle of a feral cat colony, so they move off the block. The male rats follow."