Many of us often find ourselves wondering what our beloved animals may be dreaming of, when they twitch, snuffle, and even call in their sleep. Is our elderly lap-cat dreaming they are a ferocious lion prowling the savannah, is the dog we share our house with dreaming of the forests and streams we explored together that day? Might they even have that recurring dream of soaring over the city with Dumbo or running from some gruesome unknown monster like we do? Who really knows what goes on in the mind of animals and what they dream about – is it even possible to find out?
In Ancient Greece, Aristotle asked the question, "do animals dream?" in a book he wrote about sleep over 2,300 years ago. He believed that all animals need sleep like humans do, and that they also dream. As evidence, he pointed out that dogs bark in their sleep, and that other animals also move and sometimes make sounds in their sleep, similar to humans. He stated that it was clear that animals experience things that are only in their imaginations, like we do. Today this would not be taken as convincing scientific proof, but as we will see, modern science has been able to prove what Aristotle understood intuitively.
Today we are of course much more equipped to investigate the question of whether and how other animals dream – tools that Aristotle could not even dream of. Today we are able to document and analyze the behaviors of animals during what most of us would intuitively identify as dreaming activity – and to directly record brain activity during all stages of sleep. Special devices, such as fMRI (‘functional magnetic resonance imaging’) give us amazing insights into what is happening in the brain, where, and when during sleep.
Do we find similar changes in activity in the brains of other animals as we do in our brains during sleep, and especially in the phase known as REM (rapid eye movement) sleep, when dreaming occurs?
In the middle of the 20th century, they started conducting invasive and cruel experiments on animals to learn about sleep and dreaming. Scientists removed part of cats’ brains to disable the muscle paralysis which keeps us from acting out our actions during a dream, even when we shout or run or move about vigorously in the dream. As a result, the brain-damaged cats began actually moving around and chasing imaginary objects while sleeping. This was some evidence that cats were dreaming about their everyday actions. Although this was relatively convincing proof, scientists repeated the experiments over and over again with dogs, mice, and animals of many other species.
But is it necessary to damage the brains of animals to find out what they’re dreaming about? There are, for example, animals that consciously change their colors in order to camouflage themselves in their environment. Do they change their colors even when they dream – according to the environment they dream they are in? In this incredible video, it turns out that they do!
Although octopuses, squids, and molluscs are very far from us evolutionarily, a 2012 study confirmed that they too sleep, dream and exhibit signs of dreaming very similar to those of vertebrates. And, like us, they enter a stage of sleep remarkably similar to REM sleep.
Remarkably, in 2001, scientists from MIT were able to understand not only that rats dream but also what rats dream about. Of course, we shouldn’t forget that this was only possible because these "lab rats" had been confined to such a horribly small and restricted environment for their entire lives. The scientists analyzed and mapped the firing patterns of the neurons in the rats’ hippocampus (a part of the brain that plays a central role in memory, imagination, and dream). They recorded this first during all the rats’ actions while they were awake – being confined, their possible actions were rather limited. Then they recorded the same brain activity during sleep, in the REM stage when dreaming occurs. The scientists recorded the exact same firing patterns during REM sleep. They were able to demonstrate which specific actions the rats were dreaming of – and even where (of the very limited places they were familiar with) they were dreaming they were doing each activity.
In another experiment, when researchers showed rats food just before they went to sleep, they were able to demonstrate that they were dreaming of ways to reach and eat the food.
A similar study was conducted on zebra finches. These Australian songbirds are born without songs hardwired in their brains – they have to learn them. Scientists from the University of Chicago succeeded, by studying the firing patterns of the neurons associated with each note they made while awake, to reproduce the songs the birds dreamed about: note by note. According to the scientists, the birds use dreams to practice and develop songs, similar to how sleep helps us to process information and solve problems.
So we know that animals feel like we do, enjoy like we do, and suffer like we do. Today we also have abundant evidence that they dream like we do. Animal psychology experiments are based on the enormous similarity between the cognitive structure of all animals, humans included. And yet, we arrogantly disregard the happiness, suffering, and even life of other animals – including in psychology experiments – in ways we would not wish upon the very worst of our enemies.
Maybe it's time we stop abusing our power. It may not happen overnight, but... you can dream, right?
The bottom line
Do animals dream? Definitely. They exhibit the same behavioral signs during REM sleep as we do (or the equivalent state in animals very different from us such as octopuses). Brain activity in animals demonstrates dreaming – and in certain camouflaging species like octopuses, even the changing colors of their bodies can indicate what they are dreaming about. Animals reenact events, activities, places, and interactions they experience while awake, like we do. And some animals even use dreams for developing ideas, practice, and solving problems that preoccupy them in their waking hours, like we do.
- BBC: “What do animals dream about?”
- National Geographic: “Do animals dream?”
- “Do animals dream?”
- MIT: “Animals have complex dreams, MIT researcher proves”