Scientists have observed how octopuses use their arms when hunting. The study, conducted at the University of Minnesota in the US, examined the California two-spotted octopus.
The researchers assigned numbers to the front tentacles of the octopus, whose Latin name in the scientific literature is Octopus bimaculoides.
Accordingly, from the viewer’s perspective, the octopus’ middle arm was numbered one, the right arm two, and the left arm three.
The scientists created a hiding place for the octopus in the aquarium. The researchers then released crabs and shrimp inside and filmed the octopus hunting.
In the study, it was noteworthy that the octopus followed its prey with one eye while hiding and always used the arm (number two) close to that eye in the first move.
While hunting crabs, the octopus was also seen to neutralize its prey by striking it first, as cats do.
When hunting shrimps, the octopus again used its number two tentacle first.
But since shrimps move faster than crabs, the octopus quickly activated its number one and three arms.
“Even if all eight arms of the octopus have macroscopically identical anatomy and equivalent efficiency, the use of different arms for specific actions may be related to subtleties in evolutionary adaptation,” said the study, published September 20 in the scientific journal Current Biology.
Flavie Bidel, lead author of the study, said that octopuses are generally thought to exhibit unpredictable behavior, but the research changes that.
Trevor Wardill, one of the researchers, said their next goal is to examine the role of the octopus’ nervous system in these movements.
Wardill said this could provide important information for the design of underwater vehicles and other robotic devices.