When we visited Nvidia (NVDA) earlier this month to research the Yahoo Finance Company of the Year, we noticed something unusual roaming the hallways: canines.

Nvidia, it turns out, allows and even encourages its workers to bring their dogs to work. “Dogs, as we know, get lonely,” Nvidia CEO Jen-Hsun Huang tells Yahoo Finance. “If you want to be a responsible dog parent, one way to do that is to provide them company. I see it from the perspective of the dog. It’s the right thing to do.”

Nvidia’s puppy love began informally several years ago, when one worker asked Huang if he could bring his dog to work. Sure, the CEO said: “I used to have a dog myself. I’d go home from work to see the dog during lunch.”

More dog owners started bringing their pets, and the company adopted a formal policy. Dogs have to be leashed while on campus, and attended by their owner. They aren’t allowed near food areas, for sanitary reasons. If a meeting is on the schedule, the owner has to get a co-worker to keep an eye on the dog. In some cases, dog owners have been relocated to accommodate a neighbor with an allergy or other aversion to dogs.

Since the Silicon Valley tech company occupies a sprawling, low-rise campus, there’s plenty of outdoor space for letting the dogs out, as evident in the video above. The company provides poop bags, but no staff to handle the chore; owners must clean up after their own dogs.

As our cameras rolled, several dogs frolicked in the grass, each seemingly comfortable with the others. Dog feuds are rare, Nvidia employees told us. Most dogs adjust quickly to the new digs once they start coming to work, and owners bring beds or blankets to cozy up on the floors of their cubicles, where dogs loll much of the day. Naps are often interrupted by co-workers or visitors who want to play.

A few other companies allow dogs, including Google parent Alphabet (GOOGL), Salesforce (CRM), hotel chain Kimpton and candy company Mars. (About 7% of US employers allow pets in the workplace, according to the Society of Human Resource Management.) The perk saves owners the expense of paying for a dog walker at home. Some managers say pets promote collegiality in the office, and even help reduce employee stress. Nervous about your deadline? Here, pet this.

Cats, alas, are not welcome at Nvidia, or any other company we’re aware of, because they’re less comfortable in unfamiliar places—and they occasionally provoke the dogs. Besides, the cat probably enjoys the solitude when the dog—and its owner—go to work.

Rick Newman is the author of four books, including Rebounders: How Winners Pivot from Setback to Success. Follow him on Twitter: @rickjnewman.