Laura Maloney, chief operating officer at The Humane Society of the United States, with one of her three pet rats. Maloney’s rats accompany her to work a few times a week. (Michelle Riley/The Humane Society of the United States)

Company: The Humane Society of the United States.

Locations: Gaithersburg; Washington.

Number of employees: 340.

Laura Maloney’s three rats often go to work with her — but only if they want to.

“I’ll put my arm in their cage, and if they feel like going to work — which they usually do because they’re very social — they crawl up on me,” said Maloney, chief operating officer of the Humane Society of the United States.

Once they get to the office, Thelma, Louise and Blondie spend most of the day sleeping in hammocks.

The Humane Society has encouraged employees at its Gaithersburg headquarters and D.C. office to bring dogs to work for nearly five years. Two months ago, it extended the policy to include small pets.

“It’s great for employee productivity,” said Inga Fricke, director of shelter and pet care issues. “The pets don’t have to be home alone, and their owners don’t have to worry about getting home at a certain time to feed them or take them for a walk.”

There are 58 dogs and one guinea pig currently registered for the program, as well as Maloney’s rats. All animals must be properly licensed and have current vaccinations.

“They all know each other and get along,” Fricke said of the dogs, which range from lap dogs to hound mixes and pit bulls. “When a new dog comes in, there’s an initial period of uncertainty among the animals, but they settle in after a week or so.”

Fricke, who takes her 2-year-old greyhound to work, uses a baby gate to keep the dog in her cubicle.

“She has a bed and her toys, so she just kind of hangs out,” Fricke said.

Down the hall in Maloney’s office, her three rats spend much of the day in a cage — or as Maloney, 50, prefers to call it, “their four-story condo.”

But sometimes they come out for fresh air.

“A few times a day, they’ll come out to sit on my shoulder while I’m typing or making a phone call,” she said. “It’s great for them, and it’s great for me.”