A few months ago, my boyfriend and I met up with a friend, Adam, who we hadn’t seen since the start of the coronavirus pandemic. We sat in the backyard of his Pawtucket, R.I., apartment — physically distant and donning masks — and roasted marshmallows over a fire pit. But the party really got started when a few unexpected guests showed up.

“What was that?” I asked, eyeing the fence to our left. We heard the scratching sound again and saw a large dark shape skitter by.

“Rats,” Adam said. “There are so many of them. … It’s disgusting.”

During the height of the pandemic, people around the country, including my friend, began to report that they were seeing rats in large numbers, even in broad daylight.

“Our city, like many cities across the country, has seen an increase in rodents amidst the pandemic,” Emily Koo, sustainability strategy manager for the city of Providence, said at a late-August meeting of the Providence Environmental Sustainability Task Force.

But the truth is, the rats were always there; we just didn’t notice them.

“One reason a lot of people are seeing rats more is because we’re home more now,” said Tony DeJesus, technical director for Providence-based Big Blue Bug Solutions.

His company has noticed a 20 percent increase in calls about rats since the pandemic hit.

“We noticed an uptick in pest control for things like ants, too, because people notice them now because they’re in their house all the time,” he said. “So for rats, maybe you’re having people over and you’re all sitting socially distanced in your yard, and all of a sudden something runs through and you see it.”

Cue my experience with my Pawtucket friend. But another part of the uptick in calls about rats is because when the pandemic hit, rats, like humans, were thrown for a loop.

“The pandemic has caused disruptions to rat populations on a global scale,” said noted rodentologist Robert “Bobby” Corrigan. “I hear from every city that we see rats during the day, we see them in areas we never used to see them. And it all makes sense. These rat populations depend on us.”

Corrigan has been studying rats for years and has crisscrossed the country helping cities with their rodent problems.

“I tend to gravitate towards things that other people don’t,” he said. “All my buddies wanted to study whales, butterflies, the glamour species, and I swim the other way.”

And Corrigan didn’t just sit in laboratories observing rats and taking notes, he actually moved in with rats and observed them in their natural habitats. “It was the best time of my life,” he said.

Needless to say, Corrigan knows rats better than most of us, so when he began to hear talk about hordes of “aggressive” rats fleeing barren restaurant wastelands and fighting over scraps of trash on people’s front stoops, he knew that it was more complicated than it seemed.

Rats are scavengers and hunters, and like a human concerned about healthy living, they try to eat a balanced diet. And one of the best places they can get a well-rounded meal? Restaurants.

“Restaurants are a key factor because they generate copious amounts of food,” Corrigan said. “A rat near a restaurant can get everything they need. They want the same thing that we want: they want some sweets, they want some fruits and vegetables, they want protein more than anything, that’s their goal, and fats. So, rats will literally eat right out of a grease trap and love it because grease is full of everything I just said.”

Rats are normally most active between 10 p.m. and midnight, and later around 4 a.m. They mostly go out of their way to avoid contact with humans, which is why it surprised people when they started to see them in broad daylight.

“Most people don’t realize that when we go home and go to bed, that’s their time,” Corrigan said. “And by the time we get up in the morning and go back to work, they’re all back in their beds. So, they’re off our radar screen except for now.”

When restaurants shuttered during the height of the pandemic, rats were stripped of a major food source, forcing them to adjust their feeding times to see if they would have better luck at different times of the day.

“I call them disoriented rats. Just like we are. We’re all inside or working from home and if someone was looking at us as a species … they’d say well, these human beings are acting different,” Corrigan said. “Rats are saying the same thing. They’re like, yeah, we used to go out at night, food would always be there. Where’d it go? I better get up in the morning and try the daylight to see if the food’s gone to daylight.”

Hence the idea that there are more rats than ever when really they’re just another animal trying to survive a challenging time by adapting their lifestyle, something they’ve been historically good at.

“The Norway rat and the house mouse are the number two and three most successful mammals on planet Earth,” Corrigan said. “And the reason is they adapt. You can take a rat and throw it in the middle of nowhere, and it’s gonna say, ‘Fine. I’m gonna make a life here. I can do this.’”

Corrigan has seen this on extreme levels, once finding a rat’s nest inside of a hollowed-out loaf of bread left under an oven in a bakery. And in the case of the pandemic and a loss of a consistent food source, adapting means braving daylight — and humans — to find a meal.

But before you reach for a remedy to rid yourself of a rat problem, check your yard for burrows to see if you really do have a problem.

“You can see a rat run through your yard, but that doesn’t necessarily mean you have rats in your yard,” DeJesus said. “But that could mean that they’re in your area, so you need to now check your yard, check for burrows.”

Burrows have an entrance that is a few inches across with a tunnel that inclines downward. There may be multiple holes, some of which are used as “bolt holes” for quick escape. DeJesus also suggested checking in shrubs and overgrown areas of your yard.

Corrigan and DeJesus also suggested seeking out what could be attracting rats to your area in the first place.

Garbage is a big draw, as is dog waste and any food scrap that doesn’t make it to the trash.

“If there’s an apartment complex or even someone’s house nearby, and they don’t do their garbage correctly … believe me, the rats know,” Corrigan said.

Leah Bamberger, director of sustainability for the city of Providence, said trash is the biggest attractor of rats and cleaning it up is a great way to address the problem.

“So long as there’s a source, which is trash, food dumpsters, there will always, always, always be rodents in cities,” she said at the Aug. 24 Environmental Sustainability Task Force meeting. “The best way to address a problem is to reduce the source of food. So, we really want to help get message out that where there is trash, there will be rodents.”

Editor’s note: Emily Koo is an ecoRI News board member.