He urged her to obtain more video that could be used to more clearly see how they walk, and encouraged her to publish the observations.

All these movements are accomplished through muscles that squeeze and bend the fluid-filled arms and body.įull said he was 'blown away' when Huffard showed him video of the octopuses last year. Normally, it crawls over the bottom of the ocean, pushing and pulling with the suckers on its eight arms, or jets backwards through the water.

It keeps its shape not with an internal or external skeleton but by hydrostatic pressure, sometimes called a hydrostatic skeleton or muscular hydrostat. 'This bipedal behavior allows them to get away and remain cryptic,' said Huffard.Īn octopus is basically a water-filled balloon,īut with the fluid contained in muscle cells rather than an open cavity. Octopuses camouflage themselves by changing both color and shape, but when startled and forced to move quickly, they have to give up their camouflage. Huffard and coauthor Robert Full, professor of integrative biology at UC Berkeley, think that this bipedal walking is a strategy octopuses use to backpedal away from predators while remaining camouflaged. This specimen was captured along Australia's Great Barrier Reef. Like a weird sea monster, the octopus Octopus aculeatus walks along the floor of a tank while maintaining its camouflage as a piece of algae. 'This is the first underwater bipedal locomotion I know of, and the first example of hydrostatic bipedal movement.' 'This behavior is very exciting,' said Huffard, who first noted it five years ago in the coconut octopus but only recently was able to capture both types of octopuses on film. Huffard filmed this creature off Australia's Great Barrier Reef easily rolling over rocks and other obstacles. The other type of octopus, which camouflages itself as algae in tropical waters from Indonesia to Australia, looks like a sea monster scooting along the sea floor on two legs. This is faster than they can crawl, but probably slower than they jet around. UC Berkeley graduate student Crissy Huffard clocked the two-legged speed of one coconut octopus at two and a half inches per second, while a second individual zoomed along, backwards, at five and a half inches per second.

In Indonesia, for example, the coconut octopus looks like a coconut tiptoeing along the ocean bottom, six of its arms wrapped tightly around its body. When walking, these octopuses use the outer halves of their two back arms like tank treads, alternately laying down a sucker edge and rolling it along the ground. This first report of bipedal behavior in octopuses, written by University of California, Berkeley, researchers, will be published in the March 25 issue of Science. More video: The octopus Octopus aculeatus maintains its algae-like camouflage while walking backwards on two arms, using the outer part of each arm like a conveyor belt. The Indonesian coconut octopus, Octopus marginatus, scoots along the ocean floor using the tips of its arms. By Robert Sanders, Media Relations | 24 March 2005īERKELEY – Two species of tropical octopus have evolved a neat trick to avoid predators - they lift up six of their arms and walk backward on the other two.

Coconut octopus