Scientists have finally managed to discover how the octopus manages to coordinate all its eight arms and move without tangling them. The researchers discovered the answer to this mystery by performing a kinematic analysis of the arm coordination. The study was published in the journal Current Biology.
The research was conducted by scientists from the Hebrew University of Jerusalem and it is the first detailed analysis of how octopuses move. Dr. Guy Levy together with Professor Binyamin Hochner filmed the octopuses as they moved from underneath and examined their movements frame by frame. It seems that the movement is done by shortening and lengthening. So, each arm pushes the body in a certain direction.
Lacking a rigid skeleton, octopuses have a unique locomotion system which is different from those met in other animals. Hochner explained that this is a cause of their soft molluscan body which provided the octopus with a strange morphology and so enables them to move efficiently even without a rigid skeleton.
According to Dr. Levy the octopus has found a simple solution to a problem which seemed complicated. When moving all the octopus needs to do is decide which arm it wants to use for pushing, not in which direction the arm will push. Since the octopus has 8 legs they just have to push whichever leg they wish and they will move in any direction irrespective of what way their body is facing. As long as the limb movement is concerned, there is no specific rhythm or pattern.
So the movement is directed by the radial symmetry of the mollusc’s arm around the body and the mere mechanism by which the arms function to create the crawling push. The scientists explained:
“These two together enable a mechanism whereby the central controller chooses in a moment-to-moment fashion which arms to recruit for pushing the body in an instantaneous fashion.”
This discovery could be of great importance to engineers who are interested in developing biologically inspired robots. Dr. Levy explained that building soft robots could be of great use in medicine and in rescue operations. A robot with a soft body like the one of an octopus would not be hindered by fixed joints. Such a robot could be used for reaching narrow places or for helping getting trapped people out from a collapsed building.