WHO? The rats that reside in Maine are Norway rats, which are not, incidentally, from Norway. “Through genetic analysis, we now know its original origin was Asia,” said Kathy Murray, an Integrated Pest Management specialist at Maine Department of Agriculture, Conservation and Forestry. We are to blame for their presence here. They hitched a ride to America on ships in the 18th century. “They were not here before that,” Murray said. “At any rate, we are saddled with them now.”

WHERE? Aren’t rats urban creatures? What are they doing in Maine? “They are everywhere. They are coast to coast,” New York City rodentologist Bobby Corrigan said. “I travel around the world and see these animals. Paris has a bad rat problem. Rome has a big rat problem. In America, New York City is No. 1 in terms of rats.” (Not a distinction we’d want.) “After that, it’s Chicago, St. Louis, Washington, Pittsburgh. The whole eastern megalopolis is very, very ratty.”

WHY? Why do we loathe them, that is. In a word, the plague, Corrigan said, which killed some 25 million people in the 14th century. Actually, our revulsion predates the plague. “In the middle of the night, these animals come slinking into our caves with their tails dragging behind them,” he said. They “slither around on the floor and bite us. They can kill us. We learned very early on to be scared.”

Rats still carry dread diseases like leptospirosis and lassa fever.

Whatever our feelings about them, rats definitely like us – or rather, like our garbage. Murray described them as commensal animals.

In Harvard professor Hans Zinsser’s classic 1935 “Rats, Lice and History,” humans don’t come off particularly well, either. “Man and the rat are utterly destructive,” Zinsser wrote. “All that nature offers is taken for their own purposes, plant or beast. Gradually these two have spread across the earth, keeping pace with each other and unable to destroy each other, though continually hostile. They have wandered from East to West, driven by their physical needs, and – unlike any other species of living things – have made war upon their own kind.”

MAKE NICE? So is there anything about a rat to like?

For one thing, they’re smart. “Humans define smart as being able to learn and remember,” Murray said. “Rats do that. They can learn, and they can remember.”

For another, while they can make us very sick, they can also help make us well. “It sounds silly, but we should be saying thank you every single day” to rats and mice, Corrigan said. “We test all pharmaceuticals on these animals. If you need an aspirin or if you need medicine for something serious, it has to first go through rats and mice. They are the big No. 1 animal that has benefited our lives getting longer and longer.

“People are always asking me if you could get rid of all the rats, would you do that?” he continued. “My answer is ‘Heck no!’ That would be insane. However, would I vote to take out all the rats living near us? I’d say, ‘Heck yes!’ Let them do their thing, but not under my bed.”