Octopuses have similar brains to humans.
Octopuses and humans have similar brains
The sea creatures are known for their intelligence as they are able to build dens and use their tentacles as weapons.
Scientists have been able to successfully record their brainwaves by implanting electrodes into freely moving octopuses and have identified several distinct patterns - including some seen in mammals.
Researcher Dr. Tamar Gutnick, of the Okinawa Institute of Science and Technology in Japan, said: "If we want to understand how the brain works, octopuses are the perfect animal to study as a comparison to mammals.
"They have a large brain, an amazingly unique body, and advanced cognitive abilities that have developed completely differently from those of vertebrates."
Future experiments are planned that could require octopuses to perform learning and memory tasks.
University of Naples Federico II zoologist Michael Kuba said: "This is a really pivotal study, but it's just the first step.
"Octopuses are so clever, but right now, we know so little about how their brains work."