Jumping Spiders Exhibit REM-like Sleep Stages
New research reveals that Portia fimbriata spiders cycle through distinct sleep stages featuring leg twitching and eye movement.
Updated on Oct. 26, 2026 in Sleep Disorders
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Researchers at the Bonn Institute for Organismic Biology have confirmed that jumping spiders, specifically Portia fimbriata, exhibit organized sleep stages. The study shows these arachnids cycle through two distinct phases, including an active sleep state marked by retinal movement and leg twitching.
Why it matters
The discovery that spiders meet standard behavioral criteria for sleep provides new insight into the evolution of rest across diverse species. This finding challenges previous assumptions by showing that complex sleep architecture is not limited to vertebrates.
The study confirms that Portia fimbriata spiders cycle through 2 distinct sleep stages, meeting behavioral criteria such as homeostatic rebound and an elevated arousal threshold. These spiders typically clean all 8 of their legs before entering an upside-down sleep position on silken platforms.
The players
Bonn Institute for Organismic Biology
This research facility focuses on the study of organismic biology and conducted the investigation into spider sleep behaviors.
PNAS
The Proceedings of the National Academy of Sciences is a peer-reviewed journal that publishes high-impact scientific research.
The details
During the active sleep stage, spiders display characteristic leg curling and involuntary retinal movement similar to REM sleep in other animals. The study confirms that spiders demonstrate homeostatic regulation, meaning they rebound from disrupted rest periods just as other species do.
Timeline
Scientists observed REM-like activity in jumping spiders in 2022.
The full study findings were published in the journal PNAS in 2026.
The Big Picture
This study extends the traditional understanding of sleep architecture by demonstrating that complex REM-like activity is not exclusive to vertebrates. By mirroring the patterns defined in the vertebrate sleep model, this discovery shifts our view of how rest evolved across the animal kingdom.
While this study focuses on arachnids, it provides a broader understanding of why sleep is a universal biological necessity. It helps scientists refine the definition of REM-like behavior, which may eventually inform future comparative studies on human circadian health.
The takeaway
The observation of REM-like states in jumping spiders suggests that complex sleep functions are more ancient and widespread than previously thought. Future research will focus on how these sleep patterns differ when spiders are moved from laboratory environments into their natural wild habitats.
Further reading
Learn more about the science of rest in the Sleep Disorders section.
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Does evidence of REM-like sleep in spiders change how you view animal intelligence?
