Jumping spiders exhibit REM-like sleep stages

Researchers at the University of Bonn have discovered that the Australian jumping spider, Portia fimbriata, undergoes regulated sleep cycles that include a REM-like state. During these periods, the spiders exhibit eye movements, muscle twitching, and leg curling, behaviors similar to rapid eye movement (REM) sleep observed in humans and other vertebrates.

The study, published in Proceedings of the National Academy of Sciences, suggests that these sleep episodes are a regulated biological necessity. When researchers disrupted the spiders' sleep, the subjects showed increased REM-like activity following the disturbance. Behavioral tests also indicated slower response times during rest periods.

While the findings confirm an organized sleep structure, researchers noted that without direct brain recordings, they cannot definitively conclude whether these spiders experience dreaming in the human sense. The Portia fimbriata species was chosen for the study due to its sophisticated hunting strategies and complex decision-making abilities, which make it a valuable subject for studying the link between sleep, nervous system function, and cognition.