Octopus arms are highly manoeuvrable
Reaching for something can sometimes be tricky for humans, but for the octopus, it is a much trickier task.
Israeli scientists trying to work out how the octopus manages to keep control of so many flexible limbs think they have the answer.
The octopus, it seems, has some of its intelligence actually inside in its arms.
Embedded program
"The basic motor program for voluntary movement is embedded within the neural circuitry of the arm itself," German Sumbre, Binyamin Hochner and colleagues write in the journal Science.
The team, based at the Hebrew University of Jerusalem and the Weizmann Institute of Science, was able to make an octopus arm move realistically even when it was disconnected from the octopus's brain.
The researchers applied a series of electrical pulses to an octopus arm, making it flail outwards with a bend travelling out along the arm as it moved.
This characteristic movement is the same as that made by a healthy, living octopus.
Independent thinking
The implication is that an octopus moves its arms simply by sending a "move" command from its brain to its arm and telling it how far to move.
The arm does the rest, controlling its own movement as it extends.
"There appears to be an underlying motor program... which does not require continuous central control," the researchers write.
Each arm is controlled by an elaborate nervous system consisting of around 50 million neurons.
The neurons are organised as a nerve cord and nerve fibre tracts running along the opposite side of the arm to the octopus's suckers.