Sleep is nearly universal in the animal kingdom, but how animals sleep is not the same. Studies have found that in mammals, giraffes get the least amount of shut eye, while koalas can sleep up to 22 hours a day. 

There are also different types of sleep cycles—including a stage called rapid-eye movement or REM, which is often compared to non-REM sleep. A team of researchers wanted to study these different sleep cycles to understand how they might be connected to learning and memory. The scientists turned to the octopus as their study subject, selected for their complex behaviors and large brains. Their results were recently published in the journal iScience. 

Neuroscientist Sidarta Ribeiro, one of the authors on the study, joins Science Friday to explain how you measure the sleep cycles of an octopus, and what this can tell us about if an octopus might dream.

Further Reading

• Check out the full study on iScience.
• Learn more about how octopus sleep and dream in a video from Nature PBS.
• Find out more about octopus neurology and their “distributed minds” in a SciFri Macropscope video.