Octopuses are known for being able to change the color of their skin, even while they sleep.
Now scientists are trying to find out if these changes in color while resting are signs the cephalopods have two periods of sleeping — like mammals, birds and some reptiles.
Cephalopods are animals without a backbone that live in the water. They include squid, octopus, cuttlefish and nautilus. Octopuses have eight arms lined with suction cups that help them grasp objects, including prey.
If octopuses have two sleep periods it could mean they experience something like dreams.
The dreams wouldn’t be as involved as ones humans have because these periods of rest are very short, from a few seconds to a minute. But like humans, if octopuses are dreaming it could be a way for them to adapt to their environment and learn.
The octopuses were studied at the Brain Institute of the Federal University of Rio Grande do Norte, in Brazil. There, scientists found the cephalopods have a quiet period, where their skin was pale and their eye pupils were just slits. During an active sleep period the animals change their skin color and texture and moved their eyes while also shrinking their suckers and body with muscle twitches.
The cycle would repeat at about 30 to 40 minute intervals.
Octopuses have one of the most complex nervous systems of any animal without a backbone. They also have a high ability to learn, including how to open jars from the inside and the ability to identify different shapes and patterns.
Excited by their findings, the scientists would now like to record information from the octopuses’ nerves to try and understand what happens when they sleep.
— Brett French, email@example.com