- Jaejeong & Jaeah Kim
The Paradoxical Intelligence of Octopuses
(a veined octopus using a sea shell as a tool)
We recently posted an octopus dissection video (which you can check out here), where we explained the anatomy and physiology of these strange, but beautiful cephalopods. Now if you thought that octopuses couldn’t get any more interesting, did you know that octopuses are in fact highly intelligent? Out of all animals in existence, octopuses fall behind only mammals and birds in terms of intelligence, and have been observed performing magnificent escapes, using tools, navigating mazes, solving problems quickly (& remembering the solution), expressing emotions, displaying individuality, demonstrating self-awareness, distinguishing one human from another, and accomplishing many more feats of astonishing intellect.
However, scientists have discovered that there is a paradoxical aspect to such intelligence of octopuses. When studying other highly intelligent animals (such as crows, dolphins, and monkeys) in the wild, scientists discovered some key factors that all these intelligent animals share– they have big brains relative to their body size, they have a long lifespan, and they live in social groups. In accordance with these observed factors, scientists then came up with explanations as to how many animals evolved to be as intelligent as they are. The first of such explanations is the ecological intelligence hypothesis (where intelligence evolves as an adaptation to help an animal find food), and the second is the social intelligence hypothesis (where intelligence evolves as animals learn and cooperate with other members of a social group). These two explanations together, in addition to the fact that smarter animals generally live longer (suggesting that bigger brains helped longevity evolve in these animals), explains how most of the world’s most intelligent animals came to be so intelligent.
Well, here’s the thing. Octopuses have almost nothing in common with the aforementioned animals. They have a small brain (taking into consideration the fact that ⅔ of their bodies’ neurons are in their arms), have a very short lifespan (<2 years), and they live solitarily, without forming any social bonds with other octopuses. Since octopuses lack these hallmarks of intelligence found in other highly intelligent animals, they obviously have not evolved to be intelligent in the same way other intelligent animals did. So how exactly did the astonishing intelligence of octopuses come to be?
Scientists predict that ~275 million years ago when the ancestors of octopuses lost their external shell, they were left vulnerable, and this threat was what drove octopuses to develop their great intelligence. However, even after understanding the evolutionary background of octopus intelligence, questions still remain. If octopuses are so intelligent, why do they die so young? Intelligence seems not to have given octopuses much of a long lifespan, and thus octopus intelligence remains to be a paradox of natural selection– Octopuses, the short-lived, but highly intelligent animal. Scientists hope that deeper research into octopus intelligence may reveal a deeper understanding of animal intelligence in general, that may prove useful in human applications as well.