A new study has found that jumping spiders can enter a state similar to REM sleep, similar to what humans and other mammals experience.
The researchers plan to continue to investigate what benefits entering such an immobilized resting state could bring.
The study’s lead author suggested that spiders may even have dreams, which are linked to REM sleep.
Jumping spiders can enter a REM-sleep-like state similar to humans, a new study suggests, leading experts to theorize what they might experience in such a paralyzed state.
In the study published last week in the Proceedings of the National Academy of Sciences, lead author Daniela Roessler and her colleagues looked at baby jumping spiders, specifically the Evarcha archaea species, overnight
Roessler told The Washington Post that he noticed that the spiders were “hanging really well, overexposed, not in a silk retreat” and were almost immobile, intrigued the researchers involved in the study.
“It was the most unusual thing I’ve ever seen,” Roessler told the Associated Press of the immobilized and largely vulnerable creatures.
The footage revealed behavioral patterns in the baby spiders that largely resembled a state similar to REM (retina eye movement) sleep: twitching their legs and quivering “retina tubes”, a part of the spider’s eye that allows its eyes move and was visible through the jumping spider’s translucent exterior. REM sleep has also been linked to dreaming due to the high brain activity seen in humans and other mammals such as cats and dogs.
“These contractions felt so classic and immediately reminded me of a dog dream,” Roessler, who is also a behavioral ecologist at the University of Konstanz in Germany, told The Post.
“Whether that means they are visually experiencing it in a similar way to how we experience visual dreams is an entirely different story,” Roessler continued.
Prior to the study, Roessler told The Post that little was understood about spider sleep patterns — or REM sleep in mammals, birds or other creatures as a whole — but she and her colleagues plan to test whether spiders’ REM sleep it works. how the state really is sleep in scientific terms, and what benefits creatures could reap from entering such a state.
“The assumption is more like they just get some rest during the day or… whenever they’re active,” Roessler said. “But I don’t think there was such a clear idea whether they actually sleep over a long period of time.”
Lisa Taylor, a researcher at the University of Florida focusing on jumping spider behavior, told The Post that jumping spiders, in particular, are extraordinarily complex creatures, both in their sensory functions and cognitive abilities.
“They’re not little robots that go out and attack anything they see,” Taylor said. “There’s a lot going on in their brains while they’re making decisions about attacking one thing or another.”
“So whether something that happens at night plays a role in that is particularly interesting,” he added.
One expert doubts it could really be REM sleep.
“There may be animals that have activity in silent states,” Siegel, a researcher at the UCLA Sleep Research Center who was not involved in the study, told the AP. “But are they REM sleep? It’s hard to imagine they could be the same thing.”
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