Scientists captured footage of an octopus exhibiting strange behaviors in a laboratory in New York, USA, which may be interpreted as experiencing nightmares.
For a month, researchers observed the octopus appearing to wake abruptly from a peaceful sleep and thrashing around, in a behavior that seems indicative of some sort of sleep disorder.
But is this octopus really having nightmares? There are several potential explanations for why the creature might act this way, and experts urge caution in interpreting the animal’s behavior too quickly – nonetheless, this behavior is certainly unusual.
The octopus filmed appears to startle from a sleep-like state and engages in behaviors that seem to be defensive against predators.
Eric Angel Ramos, a postdoctoral researcher at the University of Vermont, USA, who filmed the octopus, stated: “For all the research conducted on octopuses and other cephalopods, there is still so much we don’t know.”
The video from a lab at Rockefeller University in New York captured four episodes in which a octopus named Costello appears to be peacefully resting in a tank before suddenly flailing its tentacles wildly. In two instances, Costello also shot a jet of black ink into the water, a common defensive mechanism against predators.
Ramos noted: “It’s really strange, because it seems like it’s in pain; it appears to be suffering for a moment. Then it gets up as if nothing happened and goes about its day normally.”
The research team pointed out that some of these behaviors resemble what octopuses might do when encountering a predator in the wild. They described these behaviors in a preprint posted on the bioRxiv server earlier this month.
This led the authors to speculate that the animal may have been reacting to a negative memory during those episodes or exhibiting some form of parasitism, indicating a sleep disorder. However, they also cautioned that no firm conclusions can be drawn from these observations.
Recently, researchers have gained further insights into octopus sleep. In 2021, scientists published a study documenting evidence of a two-phase sleep pattern in these animals, including “active” and “quiet” sleep – similar to how humans oscillate between rapid eye movement (REM) and non-REM sleep each night.
In humans, most dreams occur during REM sleep, prompting some scientists to wonder if octopuses might also dream during their “active” sleep phase.
However, an expert not involved in the observations expressed caution in interpreting the octopus’s actions as dreaming.
Robyn Crook, a comparative neurobiologist at San Francisco State University, USA, asserted that we do not yet fully understand the neuroscience of animal sleep to determine whether they dream, let alone experience nightmares. And even if octopuses do dream, they may do so in a completely different way than humans.
Therefore, while the behaviors in this video are intriguing, they might very well be driven by something other than dreaming.
For instance, the octopus could have been startled by something. Crook mentioned that this octopus may have also shown signs of aging. This is a life stage for octopuses that occurs just before death, when their bodies begin to deteriorate.
The arm movements in the video seem more indicative of a lack of motor control associated with aging rather than predator evasion behaviors.
Indeed, the species Costello belongs to typically lives around 12 to 18 months, and Costello died shortly after these incidents. Ramos noted that this behavior might appear unusual because many octopuses in laboratories die before they begin to age. Additionally, most laboratories do not film their octopuses 24/7, meaning other labs may have missed opportunities to observe similar behaviors.
