Key Takeaways on Dog Dreams:

• Yes, dogs do dream. Most of our dreams, especially vivid ones, happen during rapid eye movement (REM) sleep. Importantly, Deirdre Barrett, of Harvard University says, “this stage of sleep looks very similar across all mammals.”

• Evidence suggests that dogs may have some kind of experience while sleeping. One popular theory of dreaming is the continuity hypothesis, which holds that dreams are built from the stuff of waking life.

• We dream about what we pay attention to while awake and for dogs that includes food, toys, running, chasing squirrels and, of course, us humans.

Unfortunately, animal minds are the ones we have the least access to when it comes to researching dreams. Other humans can tell us about their dreams, but our furry friends have no way of expressing what goes on behind closed eyelids. Still, most dog parents have no doubt: When a slumbering pup starts kicking and barking, there is something going on.

The science, as far as it goes, backs up that conviction. Though no one has researched dog dreams per se, we can make some educated guesses based on what we know about their close relatives in the animal world.

REM Sleep Across All Mammals

Most of our dreams, especially vivid ones, happen during rapid eye movement (REM) sleep. Importantly, Deirdre Barrett, of Harvard University says, “this stage of sleep looks very similar across all mammals.”

Whales and dolphins always keep half their brain awake, so they may not experience anything we would recognize as dreams. But other mammals, from mice to elephants, probably do.

Again, we can’t confirm that with the animals themselves. But in 2001 Matthew Wilson, a neuroscientist at the Massachusetts Institute of Technology, found a way to sidestep this problem — at least partly.

First, he monitored the brain activity of rats as they navigated a maze. Then, when the animals fell asleep and entered the REM stage, he scanned their brains again and found similar patterns of neural activation. It was as if the rats were replaying their waking experience in dream form. This fits with the idea that dreams help process and consolidate memories: By running through a task while you sleep, you can master it more efficiently.

Read More: Dogs and Cognition: How Do We Know If Dogs Have a Sense of Time?

Cats May Dream

Inching closer to dogs, we also have good reason to think cats dream, thanks to pioneering sleep research by the French neuroscientist Michel Jouvet. In the late 1950s, he discovered that a part of the brainstem called the pons plays a crucial role in regulating muscle tone during sleep. This prevents us from acting out our dreams. But when he removed part of the pons in cats, they began moving as they would while awake.

Their brains remained in REM sleep, but their bodies sprang to life — jumping, grooming, defending, attacking. “I think it’s clear […] that those cats are stalking small animals and pouncing on them,” Barrett says, “so it’s likely they have some content during those dreams.”

So, Do Dogs Dream?

All of this strongly suggests that dogs have some kind of experience while sleeping, Barrett says. What might that experience be like? One popular theory of dreaming is the continuity hypothesis, which holds that dreams are built from the stuff of waking life.

Basically, we dream about what we pay attention to while awake. For dogs that includes food, toys, running, chasing squirrels and, of course, us “hoomans.” Given how large we loom in their lives, Barrett says, they’re probably dreaming “about having fun playing with their owners, and whether their owners are perceiving them to be a good dog or a bad dog.”

That said, we know from our own dreams how wildly they sometimes differ from reality, so perhaps they have the same bizarre quality for dogs.

“Their favorite objects and activities will probably be there,” Barrett says, “but they might be happening in some surreal or exaggerated way.”

Read More: How Dogs Have Uniquely Co-Evolved With Humans Like No Other Species

How to Know If Your Dog Is Dreaming

Activity during sleep doesn’t necessarily mean your dog is dreaming. Clumsy movements and vague vocalizations can happen during other stages of sleep besides REM and may not coincide with dreams. But clear, repetitive barking or whining, as well as coordinated running movements (even if horizontal), are good indicators.

“The more elaborate it gets,” Barrett says, “the more likely it is to be acting out a dream.”

These behaviors are normal, even when they seem like signs of distress. A whimpering dog could be having a nightmare, but unless that’s combined with strange waking behavior, veterinarians say there’s no cause for worry and no need to wake them — it really is best to let sleeping dogs lie.

Article Sources

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Cody Cottier is a contributing writer at Discover who loves exploring big questions about the universe and our home planet, the nature of consciousness, the ethical implications of science and more. He holds a bachelor’s degree in journalism and media production from Washington State University.