Octopuses are smart animals that can use tools, recognize individual people, and even solve puzzles. But perhaps the most mesmerizing example of octopus intelligence occurs when they are sleeping—and, potentially, dreaming.
This week, PBS released new footage of an octopus named Heidi shifting through flashy camouflage displays in her sleep. Much like human behaviors such as sleep-talking or sleep-walking, Heidi’s multi-hued transformations may be an expression of her dreams.
“It is a very unusual behavior to see the color come and go on her mantle like that,” noted David Scheel, a marine biologist at Alaska Pacific University, who narrates the PBS documentary Octopus: Making Contact that stars Heidi.
Another dozing octopus was captured on film last year as she cycled through similar camouflage displays, according to ScienceAlert.
Scientists are not even sure why humans dream, so it will take more research to understand if octopuses experience something truly analogous to our own nocturnal visions. There’s some evidence that cuttlefish, close relatives of octopuses, display rapid eye movements that may be similar to REM sleep in humans.
Moreover, dreams are common in the animal kingdom, especially among big-brained creatures, so it seems perfectly plausible that octopuses can have them, too.
Scheel, who cares for Heidi at a tank installed in his home, speculated that octopuses might dream of catching crabs or wandering on the seafloor. In other words, he explains in the documentary, they might "see" distorted versions of mundane experiences in their sleep—just like humans do.