Dreams have the power to be moving, inspiring, uplifting, terrifying, adventurous, and so much more. When we drift off to sleep, all human beings dream. But do other animals dream, and what might those dreams be like? As it turns out, there is evidence that many types of animals, from spiders to cuttlefish to birds, go through a stage of REM-like sleep, which suggests that they may also dream.
During REM (rapid eye movement) sleep, the eyes move back and forth behind the eyelids, brain activity increases, heart rate and breathing speed up, and the body experiences instances of twitching. It is during this stage of sleep that the most vivid dreams occur.
This type of sleep was observed during a 2022 study of spiders at the University of Konstanz in Germany. Similar observations of REM-like sleep have been made of various other animals, including cats, dogs, horses, sheep, mice, opossums, octopuses, and armadillos. However, thus far, scientists have been unable to conclusively prove these animals are dreaming. After all, our knowledge of human dreams comes from our ability to verbalize our experiences. Despite this, recent studies have called into question the longstanding assumption that only humans are capable of dreaming and have made the notion of animal dreams a possibility worthy of further exploration.
To sleep, perchance to dream:
- The word “dream” was practically nonexistent in animal sleep literature until 2022, when it was first used in a scientific journal in the article “Do All Mammals Dream?” by biologists Paul Manger and Jerome Siegel.
- Researchers have observed an REM-like state in bearded dragons. They were even able to record signals from electrodes in their brains. It is also known that flies experience two or more sleep states, while roundworms have one sleep state.
- Research suggests that whales and dolphins don’t experience REM at all.