Octopuses have the largest brains of any invertebrate.

Common Octopus   © ARKive

The fact that these creatures, whose ancestors diverged from the lineage that would lead to ours roughly 500 to 700 million years ago, have developed intelligence, emotions, and individual personalities is challenging our understanding of consciousness itself.

The extreme brain to body ratio of a cephalopod sticks out when looking at its large head. But a large brain does not automatically mean high intelligence in the animal kingdom.
Another measure of intelligence is counting neurons. The common octopus has about 130 million of them in its brain. This may not sound like too many, compared to the human’s 100 billion, but this is where things get weird: Three-fifths of an octopus’s neurons are not in the brain; they’re in its arms.
Scientists who cut off an octopus’s arm (which the octopus can regrow) discovered that not only does the arm crawl away on its own, but if the arm meets a food item, it seizes it and tries to pass it to where the mouth would be if the arm were still connected to its body.

Research suggests that there is a lot more to an Octopus’s mind than we expect.

It is well-known that these animals are able to change their skin colour to blend into the surrounding environment or even mimic other animals in order to intimidate intruders.
But how does the octopus know which colours to create on its skin when they are believed to be in fact colour-blind?
New evidence suggests a breathtaking possibility. Woods Hole Marine Biological Laboratory and University of Washington researchers found that the skin of the cuttlefish Sepia officinalis, a color-changing cousin of octopuses, contains gene sequences usually expressed only in the light-sensing retina of the eye. In other words, cephalopods (octopuses, cuttlefish, and squid) may be able to see with their skin.
How that information is processed exactly may be hard to imagine, but it could be compared to dolphins, bats and other animals who orientate themselves in their environment by using echolocation as an addition to their regular eyesight.

Biologists have long noted the similarities between the eyes of an octopus and the eyes of a human.
Scientists are currently debating whether we and octopuses evolved eyes separately, or whether a common ancestor had the makings of the eye. But intelligence is another matter. Half a billion years ago, the brainiest thing on the planet had only a few neurons. Octopus and human intelligence evolved independently from each other.

It is up to us to respect these amazing creatures and learn more about them while they learn more about us.

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