A "smoothie" like this will contain rat birth control. (photo by Mary Harris)

(Mary Harris, WNYC) If you're scared of New York City subway rats, hanging out with Paul Jones is a bad idea. He's the man who manages the NY Metropolitan Transportation Authority's trash rooms, and he knows where the rats are hiding. He even knows their favorite foods.

"They want the good stuff: the Red Bull, the lattes. They love lattes!" Jones said.

Jones has watched the NY MTA try various tactics to rid itself of rodents. They've hired exterminators. They're putting trash in mint-flavored bags, which are supposed to repel pests. They've even reinforced trash room doors to make it harder for rats to make it to the buffet table.

Now they're trying a new approach. The National Institutes of Health has just given Loretta Mayer, and her company, Senestech, a $1.1 million grant to tempt rats into consuming birth control.

Mayer's product, which is still in development, works in the lab by speeding up menopause in the female rat. She's quick to add that it doesn't affect human fertility because the compound is rapidly metabolized.  "It’s just like if you take an aspirin for a headache it'll numb your headache, but if you give an aspirin to your cat it would kill it," she said.

Senestech researchers (photo by Mary Harris/WNYC)

At the moment, she's trying to find the ideal flavor to appeal to the New York subway rat's palate. In Asia, she's flavored her bait with roasted coconut, dried fish, and beer. Here, she's  considering lacing the bait with pepperoni oil. It will be mixed into a bright pink smoothie--not solid food--because underground rats can find food easily but are constantly searching for liquid.

Mayer isn't the only scientist chronicling the lives of New York's rats. At Columbia University, Professor Ian Lipkin has been sending teams of researchers into the subways to collect rodent samples. He's trying to discover what kind of germs they're carrying.

"They’re little Typhoid Marys running around excreting all kinds  of things that are problematic for humans," Lipkin explained.

Lipkin then puts the risk into perspective: he said he worries more about shaking hands with someone with a bad cough than he does about crossing paths with a subway rat. But he wants to know what the rats are carrying.

"We have every year a whole host of diseases that occur in people--encephalitis, meningitis, respiratory diseases, diarrheal diseases--that are largely unexplained. And one potential mechanism by which people become infected is through exposure, directly or indirectly, to infectious agents that would be carried by rodents," Lipkin said. "We need to know what kind of bugs these animals carry so we can respond more effectively to them."

Back underground, Mayer's research team is gathering results from the initial taste tests. They're encouraged: the rats seem to be enjoying their smoothies.

But Paul Jones has seen exterminators come and go. And even the bluntest of weapons has failed to drive the rats off. He keeps blunt objects in the trash rooms so he can lay a good whack on the aggressive rats.

Paul Jones holds the keys to all of New York City's trash rooms. And he knows where all the rat nests are. (Photo by Mary Harris/WNC)

"We've hit them with shovels and pitchforks - they just flip over and run off. And they don't go away," he says with a sigh. "They're very hard to die."

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