“Our product is not designed to eradicate any species. That’sa human error that needs to not be repeated,” said Dr. LorettaMayer, co-founder of SenesTech, the company that developed thechemical compound.”It’s a very natural thing. We’re just accelerating it inthese animals.”Female rats can produce up to 12 pups a litter, and will givebirth as many as five times during their life cycles. Thesterilization compound, dubbed ContraPest, targets the ovarianfollicles and renders the pests sterile within five to ten days ofingestion.Thomas Lamb, chief of innovation and technology for New YorkCity Transit, says the new approach is a result of the futility ofthe current methods used to combat the city’s estimated populationof several hundred thousand rodents.”We basically bait, trap and kill. If we just continue to dothat, every year we’ll have the same expense and the sameresult,” he said.Under the current methods, the city has to poison more rats thanare born, but even if it succeeds in doing so, the problem israrely solved. The surviving rats are then left with a foodsurplus, and produce large litters that quickly rebuild thepopulation.And in the unlikely scenario that all the rats would be killed,other animals from neighboring regions would quickly swoop in.The point of the plan currently in place is to create aconstant, but smaller population of older and quieter rats throughlower birth rates.Now, the problem is to get the animals to eat the poison.The rodents have highly developed taste, and can detect aslittle of two parts per million of poison in their food.”Rats in Laos, they like coconut. But the rats in Indonesiaprefer fish flavor,” said Mayer, whose product has already beenused in rural areas around the world. “You have to be very muchone with the animal.”SenesTech has been given a grant of over $1 million by theNational Institutes of Health to find the perfect bait.Dr. Robert Corrigan, a prominent rodentologist, told the WallStreet Journal that variations in taste are determined by what therats usually have in their diets.”Rats that grow up, say, from the dumpster behind a fast foodchicken place, will love chicken. Bagel place, bagels. And soon.”The bait will be flavored with different tastes and smells,potentially as varied as donuts, cookies or ham. Each one willcontain a dye that can be detected in rats’ whiskers in apost-mortem, so that scientists can see which flavor theypreferred.”We really won’t know what works until we get in there,”said Mayer.She added that if the generic bait is not successful, the poisonmay have to be placed inside discarded pepperoni slices. Butdespite such tempting packages for the poison, Mayer stressed thateating the bait would have no consequences for humans.“Well, it’s quite sweet, quite salty and there’s a lot offat. Anyone who tried it would probably gain weight from thefat,” she said.