These remarkable animals are extremely clever, whether it’s unscrewing childproof lids or effortlessly slipping through tight spaces. Dave King/Getty ImagesOzy the octopus once unscrewed a glass jar lid in just 54 seconds. This could be the record for octopus jar-opening, a trick commonly performed by these mollusks. Octopuses are so quick to learn it that, about 10 years ago, scientists at the Seattle Aquarium gave an octopus a herring-filled medication bottle with a childproof cap – the type you push down and twist. The octopus opened it in 55 minutes. With practice, it reduced the time to just five minutes.
How intelligent are these creatures, really?
The short answer: very intelligent. They can figure out how to open a childproof lid with no instructions whatsoever.
Complex answer: Octopuses evolved in conditions vastly different from humans, so understanding their intelligence would require us to reconsider what we define as "intelligence" in the first place.
Experts believe human intelligence developed largely to help us thrive in complex social settings, as Sy Montgomery discusses in her insightful Orion magazine article. One theory suggests octopus intelligence evolved to adapt to a challenging deep-sea environment without the protection of shells.
Octopuses belong to a group of mollusks known as cephalopods, which also includes cuttlefish and squid. While octopus brains are small compared to humans, they are the largest of any invertebrate, writes Montgomery. These brains are also the most similar to human brains: In most mollusks, neurons are scattered throughout the body like a web, but in octopuses, neurons form a central brain with distinct lobes that store information.
Although octopuses have fewer neurons than humans, they compensate with an abundance of brains: Nine, to be exact. Most of their neurons reside in their eight arms, and even if one arm is severed (it grows back), it can continue functioning independently. Scientists have observed a severed arm grabbing food drifting away and guiding it to where the mouth would be if the arm were still attached to the body.
As researchers delve deeper into octopus behavior, they’re finding more signs of intelligence as we understand it. Their problem-solving skills are undeniable: from opening jars (even from the inside) to escaping tanks and dismantling objects, including Mr. Potato Head. Researcher Jennifer Mather from the Seattle Aquarium has even observed an octopus showing planning and foresight: It left its den, collected three rocks from the ocean floor, stacked them, and built a rock wall in front of its entrance. Then it slept soundly behind the barrier it created.
In captivity, octopuses seem to engage in play. There’s also evidence suggesting they have individual personalities. They not only use tools, but do so in a selective and adaptive way. When Mather and her team tossed mollusks and clams with varying shell strengths into the octopus tank, the octopuses cracked the weakest shells, pried open the medium-strength ones, and drilled into the toughest (using a part of their beak as a drill). When the medium-strength shells were wired shut, the octopuses first tried prying them open, and when that didn’t work, they began drilling.
The way octopuses "think" remains largely a mystery to science, with much of the evidence pointing to a human-like intelligence being somewhat anecdotal. However, if octopus brains did indeed evolve for survival without shells, these creatures are incredibly intelligent. A large octopus can squeeze through a crack. Even more impressive is their shape-shifting ability: using layers of pigmented cells beneath their skin and their malleable bodies, they can change their color, pattern, shape, and texture to mimic a sea snake, a poisonous lionfish, a flatfish, a stingray, jellyfish, algae, coral — essentially anything that will confuse a predator.
The "moving rock" might just be the most impressive trick. An octopus perfectly imitates a rock on the ocean floor and then stealthily creeps to safety — undetected, because it moves at the exact speed light travels through the water. Predators swim right past it.
