I knew the job was dangerous when I took it ...
- Jul 19, 2004
- Out of Bounds
Researchers have only recently determined that octopuses can 'see' (detect light) via their tentacles and react to that light perception. This novel sensory capability was previously unsuspected.
FULL STORY: https://www.livescience.com/octopus-sees-light-with-arms.htmlOctopuses can 'see' light with their arms
Octopuses can "see" light with their arms, even when their eyes are in the dark, researchers have found. When the arms of the octopus detect light, the eight-armed creature pulls them close to their body.
Because octopuses generally have a poor sense of where their body is in space, this complex instinctive behavior might help protect their arms from the pincers of predators nearby that they might otherwise not sense.
Scientists have long known that octopus arms react to light. Their skin is covered in pigment-filled organs called chromatophores that reflexively change color when exposed to light. These chromatophores are responsible for the octopus's color-changing camouflage superpowers. ...
Their new experiment involved placing an octopus in a tank covered in an opaque black tarp. The octopus, kept in the dark, was trained to reach an arm through a small hole in the top of the tank to find pieces of fish. While the octopus was blindly feeling around for a piece of food, the researchers would shine a bright light on the octopus's arm at a random time; about 84% of the time when they shone the light, the octopus would rapidly pull its arm away ...
Having established that octopus arms can sense and react to light, their next step was to explore what controls this reaction. Is it a simple reflex controlled completely by neurons — or special nerve cells —in the arm, or is it controlled by the brain? ...
... the studies suggest that the arm is sensing the light, sending a message to the brain through nerves in the muscle, and the brain is telling the octopus to move the arm.
"The fact that this behavior is not a reflex, but instead controlled by higher-level cognition in the brain is fascinating" ...