Mike Carello, a rat expert with Griggs & Browne, checks out a shed with a rat infestation in Cranston.

The Providence Journal Mary Murphy

The hunt, as old as man, brings Mike Carello to a Cranston neighborhood that rats find much to their liking. The animal’s three essential requirements are available here in abundant supply. This is a fine place for them to multiply, and they do, despite their worst enemy, who comes armed with weapons not found in nature.

“This problem has been ongoing for seven or eight years that I know of,” Carello says, “where the rat population is culled or knocked down using rodenticides, traps, poisons. But they seem to come back because the opportunity is good here. The neighborhood’s good. The food, water and shelter are all provided. It’s just been a constant battle to beat the rat at its own game.”

Carello starts down the driveway toward a shed. Rats are primarily nocturnal, but they will appear during the day, especially if a tasty meal materializes on their doorstep. They have poor eyesight, but their noses are keen.

“Be very quiet and tiptoe silently because rats –– great hearing, great senses, and they’re very in tune with their environment and any changes in their environment. Remember: They’re creatures of habit. They’re not used to you peeking over, looking at them, taking photos. They’re going to run and hide.”

We proceed to the shed, quietly, hoping stealth will be rewarded.

“Be aware of your surroundings,” Carello advises. “One might just run by you.”

We pass a gas grill and proceed through a gate to a collection of recycling bins and barrels. A rusted snap trap is testament to defeat: fresh-dug earth outside several burrows and a well-tread run along a fence prove that these rats, whatever their number, and it could be dozens, are thriving. Plentiful rain has pooled in the trash cans, as convenient a water source for them as a birdbath is for birds.

Carello points to a bush bearing fruit.

“Even if the trash wasn’t here,” Carello says, “they’d consume the berries. But why would they eat the berries now when they’re eating chicken?”

But the rats do not appear. Carello, a pest-control specialist with Griggs & Browne, which has a rat-control contract with the City of Cranston, crosses the street to another house. The owner seems at wit’s end. The rats have breached the chicken wire he placed around his trash cans. They ate through newly poured concrete before it cured. He’s thinking of putting tar on the ground, gasoline on the grass seed in his shed.

“What I want to know is: Do they climb?” he asks.

“Yes.”

“Oh, great.” This is not the answer he wanted. Stephen King comes to mind.

On a purely evolutionary level, rats must be admired. Over the ages, the Norway rat, the most common rat in Rhode Island, has developed extraordinary survival skills. Also known as the brown, house, wharf and sewer rat, this species reproduces prolifically, with babies born throughout the year. They are omnivores and will eat feces and even their own young when better opportunities do not present. They run like crazy. They are excellent swimmers and jumpers.

“You can drop ’em off a two-story building and they’ll land on all fours and scurry away,” Carello says. “I wish I could jump off a building and land on my feet and run off! That’s stuff you see in movies.”

Unlike creatures guided only by instinct –– a toad, say –– rats have the capacity to learn. For example, you might put out some traps, catch some rats and congratulate yourself on victory. Ah, human folly.

“The smart ones are going to learn from the dumb ones’ mistakes,” Carello says. “They’re going to see their buddies, their relatives, get snapped on that trap. Eventually, they’re going to learn to avoid that trap. They’ll jump over it, they’ll run around it, they’ll turn around and go the other way.”

Their most enduring lesson is that while people may be the enemy, they are also major benefactors. It’s good to have a choice between berries and chicken.

“They live off of us,” Carello says. “If it wasn’t for humans, I don’t think rats and mice could survive –– or flourish like they do. They exploit our weaknesses.” They also spread disease and, with teeth that never stop growing, they gnaw through just about anything, including lead pipes, cinder blocks, and electrical wires, a fire hazard.

Carello visits a backyard where he recently encountered rats eating birdseed. They took objection.

“I was interrupting their lunchtime,” Carello says. “They were taunting me. They were running out underneath the fence here and they were coming out charging me. You know, trying to call my bluff.”

Carello has stories of rats running across his feet and rats biting children and rats emerging, desperate for air, from toilets. His Griggs & Brown colleague Tom Metcalfe has stories of his own, including the rat he tackled, the rat he grabbed by the tail and flung across a room, and the rats who grew beautiful coats living in a meat cooler, where the tenderloin was especially appreciated.

Rats generally grow no heavier than a pound, but Metcalfe found one that weighed two or more.

“I’m pulling back insulation and I was probably about a foot away from the biggest rat head I’ve ever seen in my life. Its eyes were open so I backed up slowly so it wouldn’t bite off my nose. But it didn’t move. So I kind of like went up and I poked it and it didn’t move and I took it out.”

Metcalfe’s poison had gotten it.

“Biggest rat I’ve ever seen,” he says. “At least two pounds! I kind of traveled around with it for 7 to 10 days to show everybody –– I don’t mean customers, I mean technicians. Until he started to smell and then I had to throw him away. I’m very upset I didn’t mount him.”

Live rats remain elusive. We travel with Carello to another Cranston neighborhood, where we find fresh droppings and burrows. They are here somewhere, sleeping, perhaps, or listening to sounds they’ve learned mean danger.

We have despaired of finding rats when we notice three flattened corpses in the street.

Fate, not poison, has prevailed.

“Here’s one rat,” Carello says. “It’s a juvenile. It’s a small one. Here’s another one –– another juvenile. Road kill, so to speak. And also it looks like here’s maybe Mom, Dad or someone else in the family. They were all crossing the street going to food and water or doing their daily and nightly activities. And they got caught.

“That’s pretty amazing. You’ve got all three of them all at once. Whoever was doing the driving over these guys got lucky.”

gwmiller@projo.com