Intelligent Invertebrate: The Octopus!

By Rubeena Basra | UTS Staff Writer | SQ Online (2013-14)

An eight legged creature with over a hundred suction cups on each of its tentacles lurking among the great depths of the ocean is not only one of the ocean’s top predators but also one of the most intelligent invertebrates undersea.

The octopus is a unique marine animal that has caught the interest of many individuals due to its ability to learn from others and change its behaviors to adapt to the environment in order to survive. The octopus is known as one of the ocean’s most intelligent invertebrates due to its communication skills, defense mechanisms, and learning capabilities.

Cephalopod Communication

Cephalopods exercise several methods of communication, the most common method being visual signals. Visual signals involve an array of movements of the arms, fins, and body. Octopi are also capable of displaying a variety of color changes to communicate by sending signals to other animals. Special cells called chromatophores cause the many color changes that octopi display. These specialized cells contain pigment granules that help disperse the color changes throughout the body. The different color changes serve as danger signals, protective coloring, and courtship rituals.

Cephalopods rely heavily on their chemical senses rather than their surface structures or capabilities, but this hasn’t stopped them from re-creating their own type of visual signals. They have evolved over the years and have learned to use their intricate luminescent organs to their advantage. The color changing characteristics that octopi display is significant to their survival and has helped them catch prey as well as flee from predators.

Defense Mechanisms

Octopi have learned defense mechanisms that have been advantageous to their survival. The octopi warns its predators by changing its chromatophores to a wide range of colors by discriminating different surfaces and textures with their tentacles, and using their chemical senses to imitate a similar pattern to help camouflage themselves for hunting or escaping from predators.

A well-known defense mechanism that cephalopods use to their advantage is their ink sac. This sac empties into the rectum and contains sepia, a dark fluid containing the pigment melanin. When a cephalopod is alarmed, it releases the sepia, which serves as a protective cloud to distract the predator. The cloud helps the cephalopod flee from the scene to escape from the harmful predator.

Another defense mechanism that has showcased the intelligence level of octopi is their ability to mimic other marine animals to escape predators. In the waters of Indonesia, scientists have studied the ability of the mimic octopus (Thaumoctopus mimicus) to impersonate several marine animals to escape the predation of other animals. This master of disguise octopus has been known to imitate toxic flatfish, lionfish, and sea snakes by arranging its limbs and adapting similar movements and behaviors of various animals. The octopus changes its color to similar patterns and also displays similar spots to completely impersonate the marine creature to fool predators. This defense mechanism has allowed this species of octopus to swim openly in the ocean with more freedom from potential predators¹.

Brainy Invertebrate

Octopi have been known as one of the ocean’s brainiest invertebrates. This is due to their ability to learn from imitation, observation, and positive reinforcement, as well as their problem solving capabilities. There have been numerous experiments that have proved that octopi have an impressive intellectual capacity; for example cephalopods can be taught to distinguish between certain shapes-such as a rectangle and a square and can also remember the distinction for quite a period of time.

Octopi have also displayed certain beneficial behaviors that are not seen in other marine creatures. Australian researchers conducted a study on octopi in which they found an octopus collecting coconut shell halves by stacking them and carrying them with quite some difficulty. When the octopus stopped in an open area in the ocean, it would use the coconut shells as a type of protective shield². Octopi have also been known to pick locks and take apart cages while in captivity³.

These creatures have also been known as problem solvers. They can apply different methods to a situation to reach their goal. At Chicago’s Shedd Aquarium, biologist Ernie Sawyer conducted an experiment in which she dropped a jar of frozen shrimp in a tank for a ten-pound octopus. The octopus first changed from a calm brown color to an irritated red, as a warning signal or territorial defense mechanism. The octopus finally stretched out an arm and wrapped its tip around the jar, and pulled it underneath its body. The octopus then used the strength of its suction cups and took the lid off. Observational studies have shown what these intelligent creatures are capable of with their given resources.

Octopus Survival

Octopi have used their strengths to their advantage to adapt and survive. Their intricate nervous and sensory systems, methods of communication, defense mechanisms, and learning capabilities all play an important role in understanding this creature’s intelligence. Unfortunately, it is difficult to understand the true intelligence of octopi because they are mostly studied while in captivity rather than in their natural habitat. We can only hope that in the years to come we’ll be able to gain more information about the intelligence of these fascinating creatures.


1. California Academy of Sciences (2012, January 5). Fish mimics octopus that mimics fish. ScienceDaily. Retrieved March 20, 2014, from

2. Clemmitt, Marcia. “Do Animals Think?” CQResearcher. N.p., 22 Oct. 2010. Web. 20 March 2014.

3. Goldberg, Cait. “The Octopus and the Orangutan: More True Tales of Animal Intrigue, Intelligence, and Ingenuity.” ProQuest. N.p., 9 Nov. 2002. Web. 20 March 2014.

4. Newman, Alexander A. “10 Smart Animals.” ProQuest. N.p., July-Aug. 2004. Web. 20 March 2012.

5. Roberts, Larry S., Susan L. Keen, Allan Larson, Helen I’Anson, and David J. Eisenhour. “Molluscs.” Integrated Principles of Zoology. By Cleveland P. Hickman. 14th ed. Boston: McGraw-Hill/Higher Education, 2008. 353-56. Print.