How does something decide without the possession of a brain? Until now, such a circumstance seemed nearly impossible. As research recently published in the popular science journal Current Biology suggests, a simple jellyfish organism known as Cassiopeia possesses stimuli similar to that of humans which allow it to nap.
Researchers at the California Institute of Technology have discovered that despite the absence of a brain, the possession of a nervous system allows them to reach a state of slumber. To date, these are the first known species to sleep without the use of a brain. The research consisted of the video observation of the jellyfish over the course of a 24 hour period during which pulses released by their nervous system slowed, and could be sped up again by the introduction of food. This discovery sheds light on an entirely new avenue of the abilities of simple organisms.