Jumping spiders show REM-like sleep, hinting they may dream

Researchers at Germany's University of Bonn found that the Australian jumping spider Portia fimbriata goes through distinct sleep stages, including one resembling human REM sleep. Periods of stillness were interspersed with muscle movements and eye twitches, suggesting more advanced sleep than expected. The study, published in PNAS, raises the question of whether spiders could experience something like dreams.