The human ability discovered in spiders – and amazed the researchers

A new study reveals that smart jumping spiders experience active dream sleep with rapid eye movements and body tremors, similar to humans. Researchers at the University of Bonn demonstrated through a sleep deprivation experiment that spiders biologically need this state.

A new study published in the journal of the National Academy of Sciences reveals that smart jumping spiders are capable of entering active dream sleep, similar to the dream sleep of humans and developed animals. The researchers at the University of Bonn in Germany tracked the spiders at night using infrared cameras and discovered rapid eye movements, leg tremors, and mouth twitching. In an experiment where they disturbed the spiders' sleep using fruit flies, the spiders spent nearly eighty percent more time in active sleep the next day to make up for the deficit – proof of sleep deprivation. The researchers hypothesize that dream sleep serves information processing and learning. The discovery is based on a breakthrough from 2022, when similar twitches were identified but without definitive proof. Now, the first evidence of sleep deprivation and recovery in invertebrates has been found, indicating a deep biological role for active sleep.