MARY LOUISE KELLY, HOST:
No one wants rats scurrying around their neighborhood, but they are a cunning and ever-evasive foe. Now a community near Boston is trying a different approach - rat birth control. Reporter Ari Daniel has more.
ARI DANIEL, BYLINE: I'm outside a school in Somerville, Massachusetts, with a few locals. And it seems like everyone's got a horror story about the rats here - like Adeline Lining.
ADELINE LINING: I get, like, the beautiful Bartlett pears every Christmas. And this year, they were on my porch for two hours. And then my neighbor texted me a picture and he was like, you probably don't want these anymore. No, I don't want them anymore because there were rats inside the box feasting on my Christmas pears.
DANIEL: It was a delivery.
LINING: Yeah, it was a delivery.
DANIEL: And they ruined Christmas.
LINING: They did.
ANDREW JEFFERIES: Rats are crazy.
DANIEL: Andrew Jefferies says he can't unremember (ph) the noises he heard at his last apartment.
JEFFERIES: All night in the summer, the rats would, like, scream.
DANIEL: As they, like, bathed in your trash?
JEFFERIES: Yeah. We, like, requested new trash cans. They ate through, like, the bottom and the top.
DANIEL: Besides being nuisances, the rodents cause real problems. Alicia Privett is Somerville's environmental health coordinator, aka the city's rat czar.
ALICIA PRIVETT: Rats can carry diseases, mostly leptospirosis, hantavirus. And then they also are one of the leading causes of property damage.
DANIEL: Due to the way they chew through wires, fencing, decks, even cinder block to keep their incisors trim, not to mention their extensive underground tunneling. One local health official told me when the subway was extended a mile in the '80s in neighboring Cambridge, the digging unearthed thousands of rat tunnels.
PRIVETT: They're, like, my ultimate nemesis. You got to admire their tenaciousness, their ability to adapt.
DANIEL: People like Privett have thrown all sorts of things at the problem, trying to keep rat numbers down and their vandalism contained. But residents don't always follow best practices. And the rats? They outwit our traps, penetrate so-called impenetrable containers.
PRIVETT: In my opinion, I don't think anything's rat-proof 'cause they're just so scrappy.
DANIEL: And even attempts at poisoning can backfire when pets or raptors eat the rats or the bait and get sick or die. So Somerville is trying something else - an antifertility chemical that targets female rats.
SAM LIPSON: So it basically stops the pregnancy before it starts.
DANIEL: Sam Lipson is the senior director of environmental health in Cambridge, and he's overseeing a field trial of the chemical in Cambridge and here in Somerville. Lipson says the birth control doesn't lead to permanent infertility, only while it's circulating in the rat's bloodstream. The goal, however, is not total eradication.
LIPSON: That is not going to happen. The idea of bringing the sea level down is sort of the way I think about it because other types of bait and efforts to minimize rat activity are going to be way more successful if you can bring the overall population down.
DANIEL: So Lipson and his colleagues are testing whether this chemical, when dispensed in bait boxes in a dense and variable urban environment, might lead to less overall rat activity.
LIPSON: And if we find that it does, I think we'll make that part of our city strategy.
PRIVETT: All right, let's go get this started.
DANIEL: The field trial relies on community volunteers, and Alicia Privett's leading four of them on an orientation.
PRIVETT: We're going to head over this way.
DANIEL: She walks through how to look for rodent activity and check the bait boxes that are in a handful of people's yards in this part of Somerville.
PRIVETT: You just push in, it'll pop up.
(SOUNDBITE OF BAIT BOX OPENING)
DANIEL: Over the course of a year or so, the city will gauge whether the approach helps. Donene Williams, a longtime resident of Somerville, is one of the volunteers. Her job will be to search out evidence of rats and fill the boxes with the antifertility bait.
DONENE WILLIAMS: I have no illusion that we can actually outsmart the rats, but if we could just reduce them, that would be good.
DANIEL: She calls her involvement a form of resistance. For NPR News, I'm Ari Daniel.
(SOUNDBITE OF DAFT PUNK SONG, "INSTANT CRUSH (FEAT. JULIAN CASABLANCAS)") Transcript provided by NPR, Copyright NPR.
NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.
