Octopus Intelligence: How Do You Measure the IQ of an Octopus?

Estimated reading time: 13 minutes

From unfastening lids to slipping through drainpipes, octopuses demonstrate remarkable problem-solving both in labs and in the wild. In this article, Dr. Alex Schnell, comparative animal psychologist and host of National Geographic’s Secrets of the Octopus, explores four key pillars of intelligence: behavioral flexibility, imagination, reasoning, and memory/foresight. By the end, you might just wonder whether humans are the ones taking the wrong IQ test.

Inky the Octopus Escapes From a New Zealand Aquarium

One night at the National Aquarium of New Zealand, a covert operation took place. Inky, a young octopus, decided he’d had enough of life behind glass. When he discovered that the lid of his enclosure had been left slightly ajar, he saw the opportunity. He squeezed through the gap and, using his suckers to grip the glass, he traversed himself down the side of the tank, avoiding a jump that might have been too risky. He made his way across the aquarium floor, avoiding obstacles along the way. Eventually, Inky found a drainpipe that led to the open ocean, marking the final step of his daring escape. Inky’s escape wasn’t only a display of physical agility, it was a striking example of problem-solving and hints at a deeper kind of intelligence. 

What Drives Intelligence?

Intelligence in the animal kingdom is thought to have emerged as a response to ecological and social pressures. Ecological pressures, such as finding food and shelter, avoiding predators, and adapting to environmental changes, shape how animals interact with their environment. These pressures drive the emergence of traits such as problem-solving skills, complex memory, and foresight – particularly in changing environments where adaptability is key. Social pressures, such as navigating complex relationships, require group-living animals to minimize conflict and repair relationships after tense encounters. These pressures may drive the evolution of traits like cooperation, altruism, and perspective-taking – crucial for managing relationships, maintaining harmony, and ensuring effective interactions within the group. Species that face both pressures often exhibit the most sophisticated behaviours. In chimpanzees, environmental challenges drive tool use, while social structures refine and transmit these skills across generations.

Flexibility Over Friend Groups

Octopuses appear to have taken a different path. Their sophisticated behaviors may have evolved not out of social necessity, but as a powerful response to the constant challenge of navigating their dynamic and dangerous environments. While some species of octopuses show limited social behaviours, like brief interactions with other individuals, they don’t form the same kind of social bonds, alliances, or dominance hierarchies seen in more socially complex species. Unlike many social species, cephalopods struggle to recognize individual conspecifics or distinguish between the sexes, further distancing them from social pressures that could drive intelligence (Amodio et al. 2019; Schnell et al. 2021). Despite the absence of strong social pressures, octopuses exhibit intelligent traits that align with the four pillars of intelligence, particularly flexibility. And no, I’m not talking about their ability to stretch and contort every which way – though they certainly have no shortage of that, given they have no bones! I’m talking about their mental flexibility: their knack for adapting to new challenges and coming up with creative solutions on the fly.

The Four Pillars of Octopus Intelligence

When we think of intelligence, it’s easy to imagine it in human terms – acing an IQ test, writing a novel or mastering a game of chess. In other animals, including invertebrates like Inky, intelligence is a complex trait that is often measured through four main pillars (Emery & Clayton 2004): behavioral flexibility, imagination, reasoning, and memory, as well as foresight. 

1. Behavioural flexibility: is the ability to adjust actions based on new information or changing circumstances. 
2. Imagination: allows an animal to think beyond immediate experience, forming expectations, simulating possibilities, or innovative solutions. 
3. Reasoning: involves drawing logical connections between causes and effects to solve problems. 
4. Memory and foresight: enable an animal to recall past events and anticipate future outcomes.

Why These Pillars Beat a Single “IQ” Score

Together, these pillars provide a framework for understanding how animals navigate challenges and solve problems in their environments. Did Inky’s famous escape demonstrate the use of any of these abilities? Was it his capacity to quickly adapt to new circumstances, imagine the possible escape routes, reason through the dangers, or recall past experiences that played a role in his remarkable freedom run? Considering the complexity of his actions, it’s possible that Inky used a combination of these cognitive abilities to find his way out. 

We begin our Clever Cephalopod Chronicles by exploring the four pillars of intelligence and how they appear in different octopuses. First up: Behavioral Flexibility. Let’s dive in.

Flexibility in Disguises

Octopuses are renowned for their ability to adjust to rapidly changing environments, and their camouflage abilities are perhaps the most iconic example of behavioral flexibility. They are masters of disguise, able to instantly change skin colour patterns using specialized skin cells called chromatophores, lecuophores, and iridiphores – Read more about the fantastic phores here. Next, they level up their camouflage to alter their skin texture by using papillae – small, flexible bumps on their skin, similar to those on our tongue. This allows them to blend in with the environment’s background. Their impressive camouflage goes beyond vanishing into the seascape. They can outwit potential threats by resembling an inanimate object such as a rock (known as Masquerade) or by mimicking the appearance AND behavior of another sea creature (known as Mimicry).  

Day octopus (200 outfit changes/hour)

Picture this: On a vibrant coral reef, a day octopus moves gracefully across the sea floor, their skin color shifting to blend with the intricate patterns of the surrounding coral reef. In the span of just one hour, this remarkable creature changes their appearance nearly 200 times (Forsythe and Hanlon 1997), adjusting to every new environment they encounter, as though they were playing an intense game of hide-and-seek, and well, quite frankly, they are. This remarkable flexibility is vital for the octopus, helping them evade visual predators with unmatched efficiency. Imagine walking through a city where every street has a different dress code, and you flawlessly change outfits 200 times in an hour – so seamlessly that no one even notices. 

Look Like a Plant: The Algae Octopus Trick

The algae octopus spends much of their lives in seagrass beds and algae patches, where they can change colour and texture to match the moving algae around them. By doing so, they create the illusion (masquerade) of being just another piece of vegetation, making it harder for a visual predator to spot (Huffard 2006). 

Common Octopus: The “Moving Rock” Walk

The common octopus shows a different form of disguise with their ‘moving rock’ behavior. This species curls or tucks their front arms close to the body while using their back arms to walk across the seafloor in a conveyor-belt-like motion. This behavior makes them look like a rock on the move with occasional pauses, helping them stay undetected while crossing open, sandy areas. 

Mimic Octopus: Impersonation for Survival

Then there’s the mimic octopus, the real shapeshifter of the sea. They can alter their appearance and movements to mimic unappetising creatures like flatfish and also dangerous ones like lionfish and sea snakes (Norman et al. 2001; Hanlon et al. 2008). By mimicking animals that would make a less appealing meal or pose a greater threat, the octopus tricks predators into hesitating, giving them time to escape. 

Flexibility in Hunting

Much like their flexibility in disguise, octopuses also exhibit impressive flexibility in hunting, adjusting their strategies based on the environment and the type of prey available. When foraging for bivalves, octopuses use their highly adjustable suckered arms to either pry open the shells or use their beak to crack open the shells to get to the prey. If the shell is too thick, the octopus will use a drill-like organ (salivary papilla) to create a tiny hole, inject a toxin that paralyses the prey and breaks down the animal, making it easier to access the soft tissue–  clam chowder, yum! This remarkable adaptability shows how octopuses can fine-tune their methods, turning every hunt into a dynamic problem-solving exercise tailored to their ever-changing environment (Amodio et al. 2019).

How Octopuses Adapt Their Hunting Techniques

Unlike many predators that rely on a rigid, one-size-fits-all hunting method, octopuses are masters of adaptation, constantly tweaking their approach based on the circumstances. While big cats rely on stealth and ambush, crocodiles wait in stillness, octopuses often adjust – rarely settling on a single strategy.

The Brazilian Reef Octopus: A Case Study in Problem Solving

A fascinating example of this flexibility is seen in the Brazilian reef octopus. On the reefs off the Turks and Caicos Islands, these octopuses are known for their more secretive hunting, cautiously foraging for bivalves, gastropods, and crabs in dark and hidden spaces to avoid detection. Their tactics are calculated and subtle, working around the challenges posed by their environment.

Quick-Change Artists of the Reef

A change of environment or sudden opportunity? No problem for this octopus. The same species in Brazil can switch tactics when the situation calls for it. Occasionally, these octopuses break from their usual stealth, boldly leaping from rock pools to snatch speedy Sally Lightfoot crabs – a striking display of skill and daring. In extreme cases, anecdotal observations report them taking on unusually large prey, such as marine birds or newly hatched green turtles (Leite et al. 2009), demonstrating just how well they can adjust their tactics to suit their marine backyard.

The octopus’s extraordinary ability to adapt both its disguises and hunting strategies illustrates the depth of its behavioral flexibility, fine-tuned to navigate the challenges of an unpredictable world. These behaviors reflect an intelligence shaped by ecological pressures, offering insight into the intricate workings of these remarkable creatures. But where will this journey into the octopus mind take us next?

Next in this series, we’ll explore how imagination may play a crucial role across species, revealing yet another layer of complexity in our eight-armed friends.  Stay Tuned!

Octopus Intelligence Reference list

Amodio, P., Boeckle, M., Schnell, A.K., Ostojic, L., Fiorito, G. and Clayton, N.S. (2019). Grow smart and die young: why did cephalopods evolve intelligence? Trends in Ecology and Evolution, 34: 45-56.

Emery, N.J. and Clayton, N.S. (2004). The mentality of crows: convergent evolution of intelligence in corvids and apes. Science 306: 1903-1907. 

Forsythe, J.W. and Hanlon, R.T. (1997). Foraging and associated behavior by Octopus cyanea Gray, 1849 on a coral atoll, French Polynesia. Journal of Experimental Marine Biology and Ecology, 209: 15-31. 

Hanlon, R.T., Conroy, L.A. and Forsythe J.W. (2008). Mimicry and foraging behaviour of two tropical sand-flat  octopus species off North Sulawesi, Indonesia. Biological Journal of the Linnean Society, 93: 23-38. 

Huffard, C.L. (2006). Locomotion by Abdopus aculeatus (Cephalopoda: octopodidae): walking the line between primary and secondary defenses: Journal of Experimental Biology, 209: 3697-3707.

Leite, T.S., Haimovici, M., and Mather, J. (2009). Octopus insularis (Octopodidae), evidence of a specialized predator and a time-minimizing hunter. Marine Biology, 156: 2355-2367. 

Norman, M.D., Finn, J. and Tregenza, T. 2001. Dynamic mimicry in an Indo-Malayan octopus. Proceedings of the Royal Society London B, 268: 1755-1758. 

Schnell, A.K., Amodio, P., Boeckle, M. and Clayton, N.S. 2021. How intelligent is a cephalopod? Lessons from comparative cognition. Biological Reviews, 96: 162-178. 

Learn more here: 

The Fantastic Phores

Day Octopus-Coral Reef Crusader 

Common Octopus- Moving Rock Trick

Mimic Octopus- The Ultimate Shapeshifter