The octopus moves using a form of jet propulsion. Water is ejected from a special structure called a funnel, and the octopus is propelled in the opposite direction. Some species are well adapted to life at the bottom of the sea, able to make their way with agility on the ground and get into rocky crevices. By combining them in different arrangements, muscles can provide an impressive range of motion.
When octopuses crawl along the seabed, they contract the longitudinal and transverse muscles of their arms, lengthening and shortening their arms in turn. They twist their arms by contracting bundles of muscle fibers that wrap diagonally around them. Scientists also discovered that the octopus moves by shortening and lengthening its arms, which creates a thrust thrust. The animal doesn't move by bending or pulling its arms, which simplifies things for the creature, Levy said.
If threatened, the octopuses release an inked fluid that obscures the water, confusing the aggressor. Octopus can also change to gray, brown, pink, blue or green to blend in with its environment. Octopuses can also change color as a way to communicate with other octopuses. Octopuses are solitary creatures that live alone in lairs built of rocks, which the octopus moves into place using its powerful arms.
Octopuses sometimes even create a “rock door” for their den that closes when the octopus is secure inside. It should be convenient to have eight limbs, but also, it's a lot to keep track of. How do octopus* manipulate their limbs to move? And how is it that they can move so well, even when their eyes look in another direction? Does the octopus brain take care of the precise location and movement of tentacles that it can't even see most of the time? Other species of octopus live in deep, dark waters, which rise from below at dawn and dusk in search of food. Octopuses are likely to have developed their unique way of moving because, unlike their clam cousins, they have no protective outer shells, researchers said.
To learn more about the locomotion of these intelligent creatures, researchers watched videos, frame by frame, of octopus crawling through tanks filled with water. Octopuses usually fall on their prey from above and, using powerful suctions that cover their arms, bring the animal to the mouth. Most octopuses remain at the bottom of the ocean, although some species are pelagic, which means they live close to the surface of the water. They discovered that the octopus brain doesn't have to do everything, because the arms, in fact, have a mind of their own.
He and the study's lead author, Binyamin Hochner, a professor at the Hebrew University of Jerusalem, plan to continue their studies on octopus. Each of an octopus's eight arms is soft, flexible and muscular, and acts as if it has an infinite number of joints, said lead author of the study, Guy Levy, a postdoctoral researcher in neurobiology at the Hebrew University of Jerusalem. Octopuses, like their cousin, the squid, are often considered “monsters of the deep,” although some species, or types, occupy relatively shallow waters. Octopuses live in coastal marine waters and spend much of their time in dens, small holes and crevices in rocks and corals.
The giant Pacific octopus (Enteroctopus dofleini), found on the Pacific coast of the United States from California to Alaska, is the largest octopus species in the world. They then plan to discover the neural circuits responsible for the coordinated tracking of the octopus, Levy said.
