Two little species of Indian Ocean octopus can tuck up six of their arms while running on the other two, U.S. researchers reported on Thursday.

They can use their other six arms to disguise themselves from predators, either as rolling coconuts or clumps of floating algae, the team at the University of California Berkeley and Universitas Sam Ratulangi in North Sulawesi, Indonesia found.

The discovery, published in Friday's issue of the journal Science, discredits theories that walking requires hard bones and skeletal muscle, as octopuses have neither.

Water, having a much higher density than air, allows octpus to "walk" but they would be unable to accomplish the same feat in air. Hence, the statement regarding needing muscularity and bones still stands for weight bearing animals in an air envirnment.

Hi All, I believe this was observed near Sulawesi which is also home to the Mimic Octopus. This wonderful creature uses various body shapes to confuse or disorient predators and prey. The most startling form involves several limbs intertwining and others waving in the current - this resembles a few sea snakes mating - and is enough to scare off most. It also streamlines all tentacles around and behind it to resemble a flatfish, and then turns vicious.
Cephalopods are definitely among the most advanced animals on the planet - imagine if we could change colour, shape and texture at will.

To all who witnessed John Kerry's performance during the last U.S. presidential election- I believe the Mimic Octopus has something to learn from HIM! He could, within seconds, become a blue collar duck hunter, an Ivy League preppie, etc. It was amazing to watch!

At Oregon State Univ Mrine science center in Newport, we had an octopus that was kept in 3 ft high 5 ft diameter cylindrical tank that was open on top so visiters could look down into the water to observe the octo. He would stay in his tank during operating hours, but at night he would leave his tank, crawl along the floor and enter other tanks (to eat crabs). He was using all eight legs to move through the air and could travel at least 30 feet to the tank he was interested in so he must have held enough water in his mantle to provide oxygen for himself until he got to the next tank. His was one of the few tanks with concrete sides and viewing from the top. The tanks he crawled to were glass fronted and the tops where he would enter were about seven feet off the floor so with his suction cups he would climb up the glass fronts and enter his desired tank (replenishing his water/oxygen supply and sometimes replenishing his stomach contents!) They truely are very intelligent animals even though they have no bones, I guess we could say they are "spineless". but like many preditors very smart as seen in this news story and the other comments from previous contributors. He was a Pacific giant octopus caught locally near Newport.

The walking behavior isn't purely limited to Octopi. I saw another Cephalapod, a Cuttlefish, "walk" using two of it's appendages at EPCOT in The Living Seas exhibit last weekend, albeit for less than 30 seconds.

Cephalopods are right up there in evolutionary terms, several can 'breathe' for some time out of water and use this to pursue slow prey up beaches, over rocks etc. Would be interesting to see how they coped in space.