DO ARACHNIDS DREAM OF INVERTEBRATE SHEEP?

Jumping spiders may have a Rem-sleep-like state.

Similar to the active sleep of dreaming humans, jumping spiders (Evarcha arcuata) might have a rapid eye movement (REM) sleep-like state as well – according to new research in PNAS.

Researchers analysed nocturnal infrared footage of 34 juvenile jumping spiders and found that the spiderlings exhibited consistent periods of retinal movements at regular intervals, coinciding with body movements that are commonly associated with REM sleep in other animals.

“The combination of periodic limb twitches and eye movements during this sleeplike state, as well as the increase of duration of REM sleep-like bouts, meets core behavioural criteria of REM sleep observed in vertebrates, including humans,” the authors say.

“Eye movement patterns during REM sleep have been hypothesised to be directly linked to the visual scene experienced while dreaming – begging the deeper question of whether jumping spiders may be experiencing visual dreams.”