Science shows that animals, including dogs, do dream!
I wanted to republish a recent and serious article written by George Monbiot but couldn’t bear to push back against the wonderful video of yesterday. Those loving ripples are still spreading across my consciousness and, I’m sure, that’s the same for you.
Consciousness, sleep, and dreaming are fascinating states of the mind. Previously thought exclusively the states of human minds. But not so!
By: Care2 Causes Editors October 22, 2017
Written by Sy Montgomery, coauthor of Tamed and Untamed: Close Encounters of the Animal Kind
The electric eel exhibit at the New England Aquarium has a feature that makes it a favorite. Whenever the eel is hunting or stunning prey, the charge powers a voltmeter above his tank. It lights up when the eel is using his electricity, and allows you to see the invisible—like magic.
One day I saw another magical thing happen in the tank. Thanks to the voltmeter, I was able to watch the eel dream.
It happened when I was standing in front of the exhibit with Scott Dowd, the lead aquarist for the freshwater gallery, watching the eel resting motionless at the bottom of the tank. “I think he’s asleep,” I said to my companion.
“Yes, that eel is catching some serious z’s,” he agreed.
Being hard-core fish enthusiasts, we continued to watch transfixed while the electric eel slept. And that’s when it happened: A big flash shot across the voltmeter display—and another and another.
Electric eels hunt while swimming forward, wagging their heads to and fro, sending out electric signals that bounce back to them, sort of like a dolphin’s echolocation. But he was still motionless. So what was the flash for?
“I thought the eel was asleep!” I said to Dowd.
“He is asleep,” he replied.
We realized at once what we were almost surely witnessing. The electric eel was dreaming.
“It would appear that not only do men dream,” Aristotle wrote in History of Animals, “but horses also, and dogs, and oxen; aye, and sheep and goats. . . .”
It was obvious: Like most of us, Aristotle had watched sleeping dogs twitch their ears, paddle their paws, and bark in their sleep. Surely other animals dreamed as well.
But since Aristotle’s day, more “modern” thinkers denied that animals could dream. Complex and mysterious, dreams were considered the exclusive province of so-called higher minds.
As brain research advanced, however, researchers were forced to concede that Aristotle was right. Animals do dream.
And now we are even able to glimpse what they dream about.
Since the 1960s scientists have understood that our dreams happen during the rapid eye movement (REM) phase of the sleep cycle. During this time our muscles are normally paralyzed by the pons of the brain stem, so that we don’t act out our dreams. In 1965 researchers removed the pons from the brain stems of cats.* They discovered the cats would get up and walk around, move the head as if to follow prey, and pounce as if on invisible mice—all
By 2007 we would get an even more vivid picture of animals’ dreams. Massachusetts Institute of Technology scientists Matthew Wilson and graduate student Kenway Louie recorded the activity of rats’ brains while the animals were running a maze. Neurons fire in distinct patterns while a rat in a maze performs particular tasks. The researchers repeatedly saw the exact same patterns reproduced while the rats slept—and they saw this so clearly they could tell what point in the maze the rat was dreaming about and whether an individual rat was running or walking in his dreams.
The rats’ dreams arose from the hippocampus, the same area in the brain that seems to drive humans’ dreams. It’s an area known to record and store memories, and that supports the notion that one important function of dreams is to help us remember what we have learned. Of course, it’s important to a lab rat to remember the right way to run a maze.
So if rats dream of running mazes, what do birds dream about? Singing.
University of Chicago professor Daniel Margoliash conducted experiments on zebra finches. Like most birds, zebra finches aren’t born knowing their songs; they learn them, and young birds spend much of their days learning and rehearsing the song of their species. While awake, neurons in the forebrain known as the robustus archistrialis fire when the bird sings particular notes. The researcher was able to determine the individual notes based on the firing pattern of the neurons. While the birds were asleep, their neurons fired in the same order—as if they were singing in their dreams.
Much less work has been done on fish than on mammals and birds. No one has found REM sleep in fish—yet. But that does not mean they don’t dream. Interestingly, no one has discovered REM sleep in whales, either. But whales almost surely dream. They are long-lived, social animals with very big brains much like our own, and for whom long-term memory consolidation is crucial.
And if you were looking for rapid eye movement in sleeping owls, you’d never see it—because owls’ eyes are fixed in their sockets. That’s why they need to turn their heads around, Exorcist-style. Yet owls’ brain waves show they dream, too.
Fish do sleep, however—that much is well known. It’s been carefully documented that if zebra fish are deprived of sleep (because pesky researchers keep waking them up), they have trouble swimming the next day—just as a person would have trouble concentrating after a dreamless night.
What might an electric eel dream about? The voltmeter at the New England Aquarium showed us the answer: hunting and shocking prey.
This excerpt is from Sy Montgomery and Elizabeth Marshall Thomas‘ Tamed and Untamed: Close Encounters of the Animal Kind (Chelsea Green Publishing, October 2017) and is printed with permission from the publisher.
*Care2 stands firmly against animal testing and believes it to be a cruel and unnecessary practice for which there are viable alternatives, such as computer modeling.