But what we often forget to mention on that list is the octopus. The octopus, along with cuttlefish and squid belong in the cephalopod class of molluscs. They are thought to be some of the most intelligent invertebrates. Octopus, along with other species in that group presents a great example of advanced cognitive evolution in animals.
And how can the octopus not be among the most intelligent species in the world? After all, an octopus has three hearts and nine brains. Two of the hearts pump blood to the grills, while the third one circulates it t the rest of the body.
The nervous system of the octopus is composed of a central brain, combined with a large ganglion at the base of each arm. Basically, each arm has its own brain that controls movement.