From nature.com: Octopuses have a preferred arm. [Update: article now available only to subscribers.]
Most octopuses have a favourite arm, zoologists have discovered. This is the first time they have been found to show any bias when choosing which of their eight limbs is right for the job.
The creatures use their trusty first-choice appendage when exploring a new nook or cranny, says Ruth Byrne of the University of Vienna in Austria. She presented the discovery on Sunday at the annual meeting of the Animal Behavior Society in Oaxaca, Mexico.
In terms of skill, octopus arms are created pretty much equal. "All eight arms are capable of the same tasks," Byrne told the meeting. "There's hardly any specialization."
This had prompted experts to suspect that the creatures simply use whichever arm is handiest. Indeed, one of their preferred hunting strategies is to jump on top of a rock and curl all of their arms underneath, grabbing whatever they find.
But when Byrne and her colleagues placed unfamiliar objects into an octopus's tank, or presented the animals with a T-shaped cavity to explore, each individual tended to favour one of its limbs when investigating. [continue]
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