An octopus is cephlapod mollusca of the order octopoda, having eight sucker bearing tentacles, a soft sac-like body, a strong beak-like jaw, and no internal shell. Like all other cephlapods, octopuses are bilaterally symmetric and are mostly characterized by their large prominent head, called a mantle, and their long tentacles(13). According to many scientists "[o]ctopuses and other cephalopods such as squids are thought to be the most intelligent invertebrates, but the nature of their intelligence is still a mystery" (15).

Often Ignored Characteristics:

Internal Anatomy of an Octopus (1)

  • All octopuses are poisonous, and a few species have proven to be deadly to humans. They produce a neurotoxin in a poison gland located in their lower mantle region (13).
  • All octopuses have three hearts that are located in distinct parts of the body (13). Two of them are brachial hearts, and are located near each of the gills. The other heart is located in the upper-rear region of the mantle.
  • All octopuses, like their cousin the squid, have the ability to squirt ink. Used as a self defense mechanism, a small gland located below the stomach produces copious amounts of black ink (13).
  • All octopuses have a special protein in their blood called hemocyanin, which takes the place of hemoglobin in vertabrates. It allows them to function more efficiently in cold and low oxygen based environments (13).

What is intelligence?

Intelligence is defined as the ability to acquire information and apply knowledge or skills. Intelligence in non-human animals is called animal cognition (10). There are several topics that are tested in any animal cognition test:
Mimic Octopus (Thaumoctopus mimicus) (5)

  • Attention: The ability to focus on a single variable when faced with numerous stimuli.
  • Categorization: The ability to distinguish between numerous categories of stimuli.
  • Memory: The study of different types of memories. I.E. short-term,long-term, spatial… etc.
  • Spatial Reasoning: The ability to manage the environment, and the degree of efficency.
  • Tool Use: The ability to use parts of the environment in a manner in which it was not designed specifically for.
  • Problem Solving: Self explanatory, the ability to solve problems
  • Language: The ability to communicate within a specific species.
  • Consciousness: The ability to formulate a self concept of themselves.
In a study of animal cognition, the nervous system of animal is indirectly scrutinized. Since vertabrate nervous systems are all relatively similar, the process rarely varies but with any invertabrate, such as the ocotopus, the process of understanding its intelligence becomes foundamentaly different (10).

The Nervous System of the Octopus:

Octopus Nervous System (6)

"Meeting an octopus is like meeting an intelligent alien" (13), which is mainly due to million of years of evolution, which has allowed the octopus to develop its own nervous system, completely different from that of the vertabrates. In vertebrates, most neurons are found in the brain, but with the octopus "more than half of their 500 million neurons are found in the arms themselves" (15). Because of this, there is a common misconception that they have nine distinct brains when in fact they only have one. But located in each of their tentacles is a single ganglion.

These ganglia are a bundle of nerves that are found in the base of each tentacle. They act as relay centers between the perepheral and central nervous systems. In octopuses, the ganglia contain autonomic nerves that contain involuntary motor skills that is normally mapped, and stored in a vertbrate’s brain.

The Brain of the Octopus:

The octopus brain is fundamentally different from any vertabrate due to its position in the body, its design and functionality. Unlike any vertabrate, the octopus’ brain is located directly above its mouth and below its “head.” It surrounds the esophagus, using it almost like a spine for stability purposes. It does not sit in any vestiage, and is not protected by any hard tissue (13).

Similar to many vertabrates, the octopus brain features folded vertical and subfrontal lobes, which serve as distinct centers of thought: specifically memory and visual (13). The brain has also indicated a lateralization, where one hemisphere is used for specific functions. This is immediately seen in the octopus’ monocular vision where one eye is consistently used more than another. Studies have indicated that the brain when measured for electrical outputs, does perform similar to that of a dog. More studies, and tests have argued that the brain enables them to have both short and long-term memories.

For such an arguably evolved brain, it does lack some functions that are common in many vertabrates. It does not have somatotopic mapping located in the brain, which means that they do not map their motor skills elsewhere in their bodies (most likely their tentacles). They also lack stereogenius, which means they cannot form a visual mapping of anything that they touch. In many ways the octopus brain is more different than alike when compared to a vertebrate's brain. According to Harvard researchers "octopus brains are striking different from those in primates (for example, 3/5 of all their neurons are actually outside the brain)" (12).

Diagrams of an Octopus Brain:

Ventral View of Brain (9)

Lateral View of Brain (8)

Octopus Dexterity:

As stated previously, the motor skills mapping is not found in the brain, rather in the ganglia (6). This might seem insignificant, but it actually illustrates the unique dexterity that the octopus possesses. Having the motor skills located in each individual tentacle allows the octopus to have predefined motions (11). This was discovered when a tentacle was severed and given an electrical charge it would move in a set of motions that were identical to those of a living octopus.

Technically an octopus has an unlimited range of motion for its tentacles. The suction cups located on the tentacles offer an incomparable grip tht allows them to seize their environment. Since each suction cup has chemoreceptors, the octopus is able to taste what they are touching (13). Unlike other cephlapods, the octopus has no vestages which allows them to fit into almost any tight space.

Traits Indicating Intelligence:

Veined Octopus (Amphioctopus marginatus) in Coconut Shell (3)

  • Cohort studies have shown that octopuses of the same species have different personalities when placed in similar environments and presented with identical stimuli. According to many, personality is only found in intelligent animals, so this discovery marks an important aspect of octopus intelligence.
  • Tool use has been seen in several species of octopuses, but it is most profoundly noted in the Veined Octopus. It is commonly cited carrying two coconut shells when travelling across open waters. The use of shells is seen as temporary shelter making, and a form of complex mimicry (2). This tool use comes to illustrate their problem solving ability.
  • It used to be believed that octopuses, like fish, did not sleep, but this has been refuted. Recent discoveries have shown that octopuses do in fact sleep, and similar to many vertabrates they do have a REM cycle (14). Almost all intelligent animals do have such cycles. REM sleep allows the brain to reset, which tends to indicate a higher functioning brain.
  • They are often considered mid level predators, but have been known to hunt and kill prey much larger. In the wild, their time spent hunting is amazing low. Only 7% of their day spent hunting, which illustrates a high level of efficiency (13). This effiecieny has inturn allowed them to hunt much larger prey with relative ease. Scientists argue whether or not this displays actual intelligence; the topic has been highly debated. In captivity they have been known to become apex predators of exhibits. In the Seattle Aquarium sharks were beginning to go missing immediately after a Pacific Octopus was added to an exhibit. It was soon discovered that the octopus had been hunting the sharks (6).
  • Like other cephalopods, octopuses present the ability to change their color to blend with the environment and to communicate. Though they are not social creatures, they have been known to flash colors to display different traits. It has more commonly been seen in squids, but in octopuses the ability to change colors has been noted. This ability is often seen present in mimcry acts (14).
  • There spatial reasoning ability was once considered hunting, but in fact it represents their ability to map their environment (13). The result is an enhanced navigation ability, which allows them to hunt and hide efficiently. In order to map a territory, an octopus presents numerous intelligence traits. First they have to recognize and memorize specific locations, and second they have to understand how to get to a point as quickly as possible.

Notable Tales:

In captivity octopuses have amazed scientists with their advanced problem solving capabilities.
  • They easily find their way through series of three-dimensional multi-level mazes with little to no practice (14).
  • When presented with a sealed jar containing a crab, it is only a matter of time before an octopus opens the jar (7). It does not matter the specific shape of the contain, the octopus always ends up getting the crab. Some believe that this test provides evidence of visual cognitive ability(14).
  • In aquariums, octopuses have been known to escape their exhibits and end up in tanks that would require travel out of water to reach (14).
  • In the wild octopuses have been known to board crab boats, and break into their holds (14). When fishermen discover them, often much of their catch is gone.

Octopus Opening a Screw Top Container (4)

The octopus surrounds the closed jar.
The octopus manipulates the still closed jar.
The octopus begins to open the jar.
The jar is fully opened.

Videos Of Octopus Intelligence:

Coconut Carrying Veined Octopus (2)

Advanced Mimicry of the Mimic Octopus (5)

Octopus Intelligence Test (7)


Diagrams, Photos, and Video:

  1. "The Amazing Cephalopoda Class, Internal Anatomy of an Octopus." The Amazing Cephalopoda Class. Web. 27 Nov. 2011. <>.
  2. Coconut-carrying Octopus - YouTube. YouTube - Broadcast Yourself. Web. 27 Nov. 2011. <>.
  3. Gelineau, Kristen. "Invertebrates Using Tools: The Coconut-carrying Octopus." Web. 27 Nov. 2011. < Invertebrates-using-tools-The-coconut-carrying-octopus/>.
  4. Kabel, Matthias. Octopus Opens Jar. Digital image. Web. 27 Nov. 2011. <>.
  5. Most Intelligent Octopus in the World - YouTube. YouTube - Broadcast Yourself. Web. 27 Nov. 2011. <>.
  6. Octopus Intelligence - Aliens of the Deep - Science Channel U.S. - YouTube. YouTube - Broadcast Yourself. Web. 27 Nov. 2011. <>.
  7. Pulpos: Suave Inteligencia (Octopus Intelligence) - YouTube. YouTube - Broadcast Yourself. Web. 27 Nov. 2011. <>.
  8. Young, Richard E., and Michael Vecchione. "Cephalopod Brain Terminology." Tree of Life Web Project. Web. 27 Nov. 2011. <>.
  9. Young, Richard E., and Michael Vecchione. "Ventral View of Cephalopod Brain." Tree of Life Web Project. Web. 27 Nov. 2011. <>.

Articles & Other Resources:

10. "Animal Cognition (Stanford Encyclopedia of Philosophy)." Stanford Encyclopedia of Philosophy. Web. 27 Nov. 2011. <>.
11. Borrell, Brendan. "Are Octopuses Smart?: Scientific American." Science News, Articles and Information | Scientific American. Web. 27 Nov. 2011. <>.
12. Chatam, Christopher. "Platform-Independent Intelligence: Octopus Consciousness : Developing Intelligence." ScienceBlogs. 5 Apr. 2007. Web. 27 Nov. 2011. <>.
13. "Common Octopuses, Common Octopus Pictures, Common Octopus Facts - National Geographic." Animals - Animal Pictures - Wild Animal Facts - Nat Geo Wild - National Geographic. Web. 27 Nov. 2011. <>.
14. Montgomery, Sy. "Inside the Mind of the Octopus." Orion Magazine. Web. 27 Nov. 2011. <>.
15. Powell, Alvin. "Thinking like an Octopus | Harvard Gazette." Home - Harvard Public Affairs & Communications. Web. 27 Nov. 2011. <>.
16. Zimmer, Carl. "How Smart Is the Octopus? - Slate Magazine." Slate Magazine - Politics, Business, Technology, and the Arts - Slate Magazine. Web. 27 Nov. 2011. <>.