Article author:
Associated Press
Maddie Burakoff
New York (AP) — A question that keeps some scientists awake at night: Do spiders sleep?
Daniela Roessler and her colleagues trained and examined a baby jumping spider camera at night. The footage showed a pattern that closely resembled the sleep cycle. The spider's legs were cramping and part of his eyes flickered.
Researchers have described this pattern as "a state like REM sleep." In humans, REM sleep, or rapid eye movements, is an active stage of sleep in which part of the brain becomes active and bright, which is closely associated with dreams.
Other animals, including some birds and mammals, have been shown to experience REM sleep. However, creatures like jumping spiders haven't received much attention, so it wasn't clear if they were getting the same kind of sleep, said wrestler, an evolutionary biologist at the University of Konstanz in Germany.
Their findings were published in the Bulletin of the National Academy of Sciences on Monday.
The wrestler and her team delved into sleep questions after discovering a spider hanging at night from a silk thread in a laboratory container. She recently scooped up some jumping spiders for her research. This is a common species with a furry brown body and four pairs of large eyes.
"This was the rarest thing I've ever seen," the wrestler said of the suspended spider.
Research has shown that the overnight movement of spiders is very similar to that of other species of REM. For example, dogs and cats seem to cramp during sleep. And they happened in a regular cycle, similar to human sleep patterns.
Many spider-like species do not actually have mobile eyes, making it difficult to compare sleep cycles, co-authored a study by Harvard's evolutionary biologist. Paul Chambre explained.
However, these jumping spiders are predators that move their retinas to change their line of sight while hunting, Chambre said. In addition, young spiders have a see-through outer layer that gives the body a transparent window.
"As a biologist, you can be really, really lucky," said Chambre.
Researchers still have to figure out if the spider is technically asleep while in these resting states, wrestlers said. This includes testing if the triggers that normally turn them off are slow or not responding at all.
Jumping spider-like creatures are very far from humans on the evolutionary tree. Sleep researcher Jerry Siegel, who was not involved in the study, said it was doubtful that spiders could actually experience REM sleep.
"There may be animals that are active in a quiet state," said Siegel of the UCLA Sleep Research Center. "But are they REM sleep? It's hard to imagine that they could be the same."
But an entomologist at the University of Wisconsin at La Crosse, also in this study Barrett Klein, who wasn't involved, said it was exciting to see REM-like signs in such distant relatives. He said many questions remain about how widespread REM sleep is and what purpose it serves for the species.
REM sleep is "still a very black box," Klein said.
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The Associated Press's Department of Health Sciences is supported by the Department of Science Education at the Howard Hughes Medical Institute. AP is solely responsible for all content.
