Octopuses are among the more unusual beings in the animal world. They not only possess three hearts, nine brains and blue blood, part of their behaviour also includes the use of tools.

The use of tools was originally one of the defining features that set us humans apart from animals. Since then, an ever-growing wide variety of animals have been also observed to use tools. This ranges from chimpanzees using twigs to extricate well-hidden termites, capuchin monkey cracking nuts with rocks and bottlenose dolphins using sponges to retrieve prey from the bottom of the ocean. The list also includes crows and other birds using twigs to spear larvae, some even go as far as adapting them to their specific purpose. Invertebrates, however, had not been observed to acquire items to be used at a later stage before this study in 2009.

The intelligence of octopuses

Octopuses have proven their intelligence in a number of ways. In experiments, they solved mazes and completed tricky tasks for food rewards. They are able to recognise humans and also read their behaviour to some degree. The latter has been shown through attempts of escape whenever the researcher wasn’t looking.

Compared to all other invertebrates, octopuses have a much higher brain-to-body ratio which accounts in part for their high intelligence. It is even larger than numerous vertebrates, although not mammals. In addition, octopuses (as well as squids and cuttlefish) have evolved with a much larger nervous system and better cognitive capabilities. Each of their arms is equipped with its own brain enabling them to taste, touch and control basic actions independent from the central brain.

How octopuses use tools

Octopuses pick up coconuts to use them at a later point in time as protection from predators. They often carry them over distances of up to 20 meters along the ocean floor. They turn the coconuts so that the concave surface is on top, then wrap themselves over the coconut half, using their arms as legs in a form of “stilt walk” and tiptoe along the bottom of the ocean. During this transport the shell provides no protection from predator as the head and body are fully exposed. The benefit comes later when the octopus deploys one or more shells as a shelter to hide underneath as and when the need arises.

Julian Finn from La Trobe University in Bundoora, Australia, one of the researchers of the study recalls the first time he saw the tool wielding behaviour of the veined octopus (Amphioctopus marginatus) in Indonesia:

”While I have observed and videoed octopuses hiding in shells many times, I never expected to find an octopus that stacks multiple coconut shells and jogs across the seafloor carrying them. I could tell that the octopus, busy manipulating coconut shells, was up to something, but I never expected it would pick up the stacked shells and run away. It was an extremely comical sight -- I have never laughed so hard underwater."

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