Do spiders sleep? Scientists study baby jumping spiders to find out

A jumping spider (E. arcuata) exhibiting leg curling during a REM sleep-like state. Photo: Daniela C. Roessler/AP

It's a question that keeps some scientists awake at night: Do spiders sleep?

Daniela Roessler and her colleagues trained cameras on baby jumping spiders at night to find out. The footage showed patterns that looked a lot like sleep cycles: The spiders’ legs twitched and parts of their eyes flickered.