Brainy Invertebrate

     Intelligence originates in the brain and nervous system of the Pacific octopus. Their brains are comprised of 64 lobes and are protected by cartilaginous craniums. Surprisingly, the brain increases in both size and cell number throughout the octopus’s entire life. They also have axial nerve cords down the center of each arm to carry information to and from the brain. All eight axial nerve cords are connected by a circular nerve cord at the base of the mantle.
    Three-fifths of the organism’s nerve cells are located in their arms. Many of these nerve cells are associated with the suckers. Every single sucker has its own ganglia that connects to the axial nerve cord. These allow each sucker to report accurate touch and taste sensations on its own accord. They also each sucker the ability to move on its own accord with a lot of dexterity.     
     In nature, it has been observed that the Pacific octopus travels away from its den to hunt, and then it returns to the same den. This proves that the octopuses have spatial memory. Octopuses are also able to utilize a working memory. They leave their dens and travel one direction the first day, then a new direction the second day, a new direction the third, and so on. This hunting style uses the octopus’s working memory to remember not only how to get home, but also where it has hunted previously.    
     In the lab, Pacific octopuses have undergone tests to study the extent of their intelligence. They have successfully completed mazes, unscrewed jars, and played with Rubik’s cubes, among numerous other tasks. The octopus in the video below is able to quickly and easily open a box containing food. Pacific octopuses can also been found able to differentiate shapes. This is a greater for the octopus than humans because octopuses are not born with an automatic shape analyzer area in their brain. Thus, their ability to do so the shapes is due to pure learning.    
     Playing is another intelligent act that has been observed of these octopuses. One octopus would play with an empty pill bottle. She would use her siphon to shoot a stream of water at it. The bottle would shoot across the aquarium, toward the aquarium’s filter. Over a short period of time, the filter system would push the pill bottle back toward the octopus. She would, once again, shoot the bottle across the aquarium. She did this about twenty times in a row, for fun. After three to four days she lost the initial excitement in the task and began to be less interested in the pill bottle. This shows that octopuses use upper level thinking. They wonder what an object is, and what they can do with it.
    In captivity, Pacific octopuses even show both personalities and emotion. Some octopuses are shy, others are bold. Some are aggressive and others are fearful. When hungry, they have been found to invert their bodies, pointing their suckers upward, in a bowl shape - like a person’s begging hands. If the octopus does not receive food, he or she will swim back while turning a bright red color. This is believed to be an invertebrate’s display of the anger emotion.

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