Amazing new footage appears to show an octopus dreaming.

A clip released by Nature on PBS shows an octopus climbing to the top of a tank, settling in for the night, and then changing colours multiple times.

“If she is dreaming, this is a dramatic moment,” says Dr David Scheel, a marine biologist at Alaska Pacific University in Anchorage.

“You can almost just narrate the body changes and … narrate the dream.

“So here she's asleep, she sees a crab, and her colour starts to change a little bit,” he said as the octopus changed from white to yellow.

“Then she turns all dark. Octopuses will do that when they leave the bottom.”

From the dark colour, the octopus runs through a mix of colours including grey, yellow and black.

“This is a camouflage, like she's just subdued a crab and she's going to sit there and eat it and she doesn't want anyone to notice her,” Dr Scheel said.

“It's a very unusual behaviour to see her colour come and go on her mantle like that.

“Just to be able to see all the different colour patterns, just flashing one after another.

“You don't usually see that when an animal is sleeping. This really is fascinating.”