Dogs sleep more than half their day, so it’s normal to wonder if your pup has dreams while snoozing. Scientists say yes, dogs dream! In fact, they believe most mammals, fish, amphibians, reptiles, and birds dream on a regular basis.

The Science of Sleeping Dogs

Like people, dogs go through a few sleep stages:

• Stage 1: Slow Wave Sleep (SWS) and Non-Rapid-Eye-Movement Sleep (NREM). This is when it’s easy to be woken up.

• Stage 2: Rapid Eye Movement (REM). This is when dreams occur and you may hear your dog make noises or twitch (especially older dogs and puppies!).

• Stage 3: Slow Wave Sleep (SWS) and Rapid Eye Movement (REM). This is when your dog oscillates between light and deep sleep.

Unlike people, dogs go through their sleep cycles much faster. A typical sleep cycle is 45 minutes for your pup, while your sleep cycle lasts about 2 hours. And dogs repeat the cycle 20 or more times a day, whereas people only go through the sleep cycle 4-5 times a night.

Interestingly enough, the size of your dog affects the frequency and length of their dreams. The smaller the dog, the shorter and more frequent dreams tend to be, while larger dogs seem to have longer, less frequent dreams. 

What Dogs Dreams About

In one study, scientists disabled the pons, a structure at the base of human and dog brains that paralyzes muscles during deep sleep, and observed the movements the dogs made in their sleep. In other words, the researchers “turned off” the function that keeps people and dogs from acting out their dreams. 

What they found was that dogs seem to dream about their daily activities, much like people. The Pointers, hunting dogs, in the study acted out typical hunting behaviors in their sleep. 

So, if your dog is an avid fetch player, their dreams may consist of an exciting frisbee game–and you may notice their legs twitching. Or if your dog is a food hound, maybe their dreams are focused on mealtime scenarios, complete with sleepy sniffles. Perhaps your dog loves sniffing and dreams about following the scent of a rabbit!

Do Dogs Have Nightmares?

If you’ve ever heard your dog whimpering, growling, or whining in their sleep, you can probably guess the answer: Yes, dogs can have nightmares.

If you suspect your dog isn’t having an unpleasant dream, you can try gently calling their name to wake them up, but dog behaviorists caution you from touching your dog if they’re acting fearful or aggressive in their sleep.

Just like it can take you a few minutes to realize a vivid dream or nightmare isn’t real, waking a dreaming dog can cause confusion, which could lead to your dog accidentally acting out the not-so-happy behavior.