Sweet dreams, spidey: Arachnids experience REM sleep, and may even dream

By Jennifer Nalewicki published 1 day ago

In a new study, jumping spiders seem to exhibit similar sleep patterns to humans.



Sweet dreams: It's possible that jumping spiders dream while they sleep. (Image credit: Alberto Ghizzi Panizza/REDA&CO/Universal Images Group via Getty Images)

Imagine a spider hanging from a silky thread, as still as a corpse, until its eight legs unexpectedly tremble. While this might sound like a horror movie, it's actually a nightly experience for jumping spiders (Evarcha arcuate) who can reach rapid eye movement (REM) sleep, the stage in which most dreaming occurs, a new study finds.

In the study, published Aug. 8 in the journal Proceedings of the National Academy of Sciences(opens in new tab), researchers used cameras to examine jumping spiders while they slept, watching the motions of the arachnids’ eyes and bodies throughout the night. The twitching movements the team witnessed as the spiders snoozed was similar to that seen in humans and other mammals such as dogs, as well as nonavian reptiles and cephalopods during REM sleep.

The discovery came about unexpectedly for lead study author Daniela C. Rößler, a behavioral and evolutionary ecologist and postdoctoral fellow at the University of Konstanz in Germany. She was originally planning to study the arachnids' reactions to 3D-printed models of predatory spiders. But her research took a swift detour when she observed the spiders while they slept; at one point, she thought they were dead.

"They were all hanging from the lids of their boxes," Rößler told Scientific American(opens in new tab). "I had no idea what happened."

More:
https://www.livescience.com/jumping-spider-rem-sleep-dream