SCIENCE LAB SCENICS : OCTOPUS & MOVES

EIGHT ARMS - each with an astonishing range of movement : The eight arms of an octopus are right there in its name.

But these biomechanical marvels share more in common with appendages found in other animals. Like an elephant's trunk. Or your tongue.

That's because octopus arms are examples of muscular hydrostats, which produce force when muscle groups relax and contract against one another.

Such contractions allow for '' almost infinite degrees of freedom to bend, shorten, elongate, twist and turn,'' said Chelsea Bennice, a postdoctoral researcher at the Florida Atlantic University Marine Science Laboratory.

For a new study, Dr. Bennice and her colleagues pored over footage of wild octopuses, noting how the cephalopods flexed and twisted their arms as they explored, hunted and scrambled around.

Researchers examined two hours of video and footage each of 25 wild octopuses in a variety of habitats. They then determined four basic ways that an octopus's arm can move.

From there, Dr. Bennice's team identified 12 basic actions that octopuses perform with their arms.

Combinations of those basic actions were grouped into 15 behaviors.

The octopuses used their front arms more than their back arms. They also often used their front arms for exploring and their back arms for locomotion.

But each arm is capable of the full-range of movements and behaviors.

Other studies had hinted that octopuses showed preferences for their right or left arms. But this study did not show octopuses being '' righties'' or ''lefties'' in the wild.

The World Students Society thanks Kate Golembiewski.