Scientists have discovered compelling evidence that jumping spiders experience a structured form of sleep, including a phase resembling the rapid eye movement (REM) sleep observed in humans. The finding could help researchers better understand how sleep evolved across different groups of animals.

The research, published on October 2026, examines the Australian jumping spider Portia fimbriata, a small predator known for its sophisticated hunting strategies and ability to solve complex problems. The study was conducted by researchers associated with the University of Bonn in Germany.

Researchers Identify Two Stages of Sleep

By observing the spiders during the night, scientists identified distinct periods of rest, including episodes marked by movements of the eyes and small muscle twitches. These behaviours resemble features associated with REM sleep in humans and other vertebrates.

To determine whether the spiders were genuinely sleeping rather than simply remaining inactive, the research team monitored their behaviour and responsiveness to disturbances. The researchers also interrupted their rest to examine how the animals responded afterward.

Following disrupted sleep, the spiders displayed an increase in REM-like activity during their subsequent rest period. This response suggests that the animals may need to recover from lost sleep, providing further evidence that the observed behaviour is part of a regulated biological process.

Could Spiders Experience Dreams?

The discovery raises an intriguing question: could spiders dream?

Although the observed movements resemble some features of REM sleep, scientists have not established that spiders experience dreams in the same way humans do. The researchers also did not directly measure brain activity, meaning the underlying neurological processes remain uncertain.

One possibility is that these sleep stages support processes related to learning and memory. Since Portia fimbriata uses complex strategies to hunt other spiders, studying its sleep could help scientists investigate whether rest plays a role in maintaining or refining these abilities.

However, this potential connection remains a subject for future research rather than a confirmed conclusion.

Why the Discovery Matters

Most detailed studies of sleep have focused on mammals and birds. Evidence of comparable sleep patterns in spiders could expand scientific understanding of how sleep functions in animals with very different nervous systems.

Further investigations may examine whether similar sleep stages occur in other spider species and whether environmental conditions, including artificial light at night, influence their resting patterns.

The findings offer a new perspective on a familiar biological mystery. While the question of whether spiders dream remains unanswered, evidence of REM-like sleep suggests that the evolution of sleep may be more complex and widespread than previously understood.