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    Can an octopus get to know you?



An octopus External Link is a marine animal that has a soft rounded body with eight long flexible arms about its base which have sucking disks able to seize and hold things (as prey). The octopus is an invertebrate, meaning that it does not have a backbone.

Octopuses, squid, cuttlefish, and nautiluses make up the cephalopod group (cephalopoda, from the Latin for "head-foot"). Furthermore, cephalopods are all members of the mollusk phylum (Mollusca), making them relatives of similarly spineless snails, slugs, and oysters (mollis means "soft" in Latin) (Courage 2013b, 5). Evidence found in fossils from the Cambrian period (500 million years ago) indicates that they have been around for a long time. Although it originally had a shell, the octopus lost it during the late Jurassic (140 million years ago). The octopus lives in all seven seas.


Because it does not have a backbone, the octopus can maneuver in and out of very small spaces, often within an area comparable to the size of a human eye. The octopus has two eyes which are near-sighted and that are capable of detecting polarized light External Link (polarized light waves are light waves in which the vibrations occur in a single plane). However, it has yet to be determined if the octopus can detect color. Further, the octopus has eight arms, three hearts, blue blood (because their blood is higher in copper as opposed to iron), and suckers which can taste and grab. When observed in its natural habitat, the octopus can be seen both walking and running. It is capable of propelling itself at speeds of up to 25 mph.


The octopus is capable of rapid camouflage. This cephalopod is not only capable of changing color; but it can also modify its texture. The ink it squirts is not only used for camouflage; but, also to harm its enemies. Octopuses are known to build shelters (Mather 1995). The octopus’s ability to use its suckers to taste and grab demonstrates both consciousness and subjective behavior. In addition to manipulating objects, octopus suckers are constantly gathering information about their environment, including tactile and chemical signals (Courage 2013b, 157). Mather (1994) has also described how some octopuses improve crevices in rocks where they take shelter, enlarging the cavity by removing stones and sand and bringing stones, shells, claws from molted crabs, and even bottles to partly block the entrance. In a laboratory setting, researchers are careful to secure tanks where they have octopuses because the octopus is known to push the lids off tanks and subsequently walk throughout a lab. An octopus is capable of unscrewing a lid from a jar. Octopuses are predisposed to bipedal locomotion. In the octopus, this is achieved by the action of transverse, longitudinal, and oblique bundles of muscles in the absence of any skeletal support (Margheri and others 2011).


The octopus has a complex nervous system and is capable of learning and demonstrating memory. The neurons can be found in the arms of the octopus and each arm has between 200 to 300 suckers and a bundle of nerves that controls local movement and gathers sensory information, which it processes and relays to the brain (Judson 2016). They have been observed returning your gaze; and, they may even extend one of their arms as if inviting you on a walk to explore the ocean floor. They seem to enjoy playing with toys as they engage in play behavior and they are capable of solving simple mazes with frequency. In both laboratory and ocean settings, the octopus is known to recognize faces. Vision is well developed in this species as various visual discriminations are readily learned, and in this the abilities of the octopus are comparable with those of vertebrates (Nixon 2003). When a scientist has changed his clothing or altered his appearance in some fashion, the octopus is still able to recognize the individual; and, if they have had a previous positive experience, it is unlikely that they will squirt ink. Yes, the octopus can really get to know you.

Interesting facts:

  • The plural of octopus is NOT octopi; rather octopuses. External Link Many people will rush to show off their Latin: it must be "octopi". In fact, the —us ending is misleading; "octopus" originally comes from Greek (pous is foot). If you really want to flaunt your classics training, you should call the eight-footed creatures "octopodes".
  • Cephalopod suckers were, however, the inspiration for suction cups—both the ancient variety, made from gourds, and the modern iteration, patented in 1882. It is considered the most intelligent invertebrate (Courage 2013b, 156)
  • Albert Titus, an engineer at the University of Buffalo, has used the octopus retina as a model to build an artificial visual processing system. With the "o–retina," which is made from silicone chips, he and his team hope to diversify the type of visual information that can be gleaned from robotic explorers in exotic environments—whether in the deep ocean or deep in space (Courage 2013b, 180).
  • The Giant Pacific Octopus is the largest species of octopus in the world.
  • A lion is a mammal like us; an octopus is put together completely differently, with three hearts, a brain that wraps around its throat, and a covering of slime instead of hair (Montgomery 2015, 12-13).
  • An octopus has a beak and uses it to crush food such as crabs and mollusks in order to eat.
  • Smart, strong and flexible, the octopus is an enticing model for an entirely new kind of many-armed, multitalented robot (Courage, 2013a).
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Library of Congress Web SiteFurther Reading
  • Courage, Katherine Harmon. How to build a robot octopus. Scientific American, v. 309, Oct. 2013: 84-87.
  • Courage, Katherine Harmon. Octopus!: the most mysterious creature in the sea. New York, Current, 2013. 238 p.
  • Godfrey-Smith, Peter. Other minds: the octopus, the sea, and the deep origins of consciousness. New York, Farrar, Straus and Giroux, 2016. 255 p.
  • Griffin, Donald R. (Donald Redfield). Animal minds: beyond cognition to consciousness. Chicago, University of Chicago Press, 2001. 355 p.
  • Invertebrate learning and memory. Edited by Randolf Menzel, Paul R. Benjamin. Amsterdam, Boston, Heidelberg, London, New York, Oxford, Paris, San Diego, San Francisco, Singapore, Sydney, Tokyo, Elsevier, 2013. 588 p.
  • Judson, Olivia. The power of eight. National geographic, v. 230, Nov. 2016: 63, 66-67, 70-71, 75, 80-81.
  • Margheri, L., and others. Non-invasive study of Octopus vulgaris arm morphology using ultrasound. Journal of experimental biology, v. 214, Nov. 15, 2011: 3727-3731.
  • Mather, Jennifer A. Cognition in cephalopods. Advances in the study of behavior, v. 24, 1995: 317-353.
  • Mather, Jennifer A. Home choice and modification by juvenile Octopus vulgaris (Mollusca: Cephalopoda): specialized intelligence and tool use? Journal of zoology, v. 233, July 1994: 359-368.
  • Montgomery, Sy. The soul of an octopus: a surprising exploration into the wonder of consciousness. New York, Atria Books, 2015. 261 p.
  • Nixon, Marion, and J. Z. Young. The brains and lives of cephalopods. Oxford, New York, Oxford University Press, 2003. 392 p.
  • Yin, Steph. A genetic oddity may give octopuses and squids their smarts. New York times, Apr. 6, 2017.  Retrieved from ProQuest database on Apr. 13, 2017.

SearchFor more print resources...
Search on "octopuses," "Cephalopoda," "invertebrates," or "cognition in animals" in the Library of Congress Online Catalog.

Photo: photograph of a man holding up an octopus showing the suckers on the tentacles
Octopus suckers.
Courtesy of Nanette Gibbs.


Photo: black and white photo of an octopus with outstretched tentacles
Octopus. Prints and Photographs Division, Library of Congress.


Photo: light purple octopus
Octopus seen during a NOAA Ship Okeanos Explorer mission to explore the water column and unexplored benthic environments in the Galápagos region. Photo from the NOAA Ocean Explorer Website.


Photo: purple and white octopus
This octopus was spotted on the side of a fault scarp during a geologic traverse on the Submarine Ring of Fire 2002 expedition. Photo from the NOAA Ocean Explorer Website.

Photo: green and orange octopus among rocks
Used with permission of Mark Llewellyn.

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 August 14, 2017
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