NYC Subway Fights Rats —With Sterilization ContraPest makes female rats infertile, if they eat enough of it By Mark Russell, Newser Staff Posted Mar 12, 2013 11:43 AM CDT 26 comments Comments A rat wandering the subway tracks at Union Square in New York, from June 15, 2010. (AP Photo/Frank Franklin II, File) (Newser) – The rats of New York's subways have outfoxed poisons and traps alike, but now the MTA is ready to try out a new tactic—sterilization. Subway officials outlined a plan yesterday to use a sterilization product called ContraPest, which make females infertile by targeting ovarian follicles, reports the New York Times. ContraPest has been tested in Laos, India, and the Philippines, but this is the first time it has been tried in a transportation system. Plenty of challenges are still ahead, though. For the sterilization product to work, a female rat needs to eat about 10% of her body weight for five to 10 days—stiff competition given the large amounts of half-eaten snacks that can be found in the subway's garbage. "In the words of Albert Einstein, if we knew what we were doing, they wouldn’t call it research," said a co-founder of the company behind ContraPest.