Scientists found a jumping spider sleeps in dreamlike stages

Scientists at the University of Bonn have found that a tiny jumping spider sleeps in distinct stages, including a REM-like phase marked by eye movements and muscle twitches. The findings, from the university's Institute of Organismic Biology, offer the first thorough experimental evidence that spiders truly sleep rather than sit around being motionless. The subject was Portia fimbriata, an Australian jumping spider about the size of a one-euro coin that hunts other spiders by imitating the vibrations of insects struggling in webs. Researchers watched individual spiders in 12-centimeter dishes using infrared cameras over many nights, then used sound stimuli to confirm the animals were genuinely asleep and not just resting. Because they could not measure brain activity, the team relied entirely on carefully documented behavior. They are careful to say the eye movements do not prove the spiders dream. Whether these spiders dream remains unknown. For now, nobody is asking them.