Let your pet snooze in peace.

You’re probably familiar with the saying, “Let sleeping dogs lie.” When it comes to your pet, there’s a reason you should follow this piece of advice literally. Dogs sleep for almost 50% of the day, clocking in an average of 12-to-14 hours. (This can vary based on your pet’s age and activity level.) There’s nothing cuter than dogs snoozing peacefully after a full day of play. Like humans, dogs can have dreams during REM sleep cycles.

Should you wake your dog if she’s experiencing what seems to be a nightmare? It’s tempting to rouse a pet showing signs of distress like whimpering, twitching, or shaking in their sleep. According to the American Kennel Club, owners should let sleeping dogs lie. “Disrupting a dog during REM sleep, which is the sleep cycle in which most dreams occur, can cause serious consequences,” says the AKC. Think about your own nightmares—you usually wake up startled and scared, and it can take a few minutes to realize it was just a dream. Dogs experience the same feeling, but more serious consequences can occur. “Like us, dogs take a moment to adjust, as well, but unlike us, when a dog is awakened in the middle of a nightmare, it can lead to an unintended bite,” the AKC says.

Experts at the Cummings School of Veterinary Medicine at Tufts University also advise against interrupting your pet’s sleep: “Consider that just like people, dogs—social and emotional animals that they are—dream to process things they have experienced, commit new things to memory, and work through emotion.” Like humans, dogs process experiences through their sleep. You wouldn’t want to be woken up in the middle of a dream without having a resolution, and your pet doesn’t either.

If you do decide to wake up your dog from a nightmare, don’t touch or shake her. “Consider gently rousing her by softly speaking her name. Don’t touch a dog to rouse her from night terrors. You could end up bitten. When she comes to, reassure her with warm words and loving petting that she is safe,” suggests the Cummings School of Veterinary Medicine at Tufts University. Showing your furry friend some TLC—like playing fetch, giving her a treat, or cuddling on the couch—is the best way to comfort her after a bad dream.