If you’ve ever looked into an aquarium tank and seen an octopus, you might have felt as if it were looking right back at you. Those watchful eyes, the rippling skin that changes colour in an instant, and the graceful movement of eight arms gliding through water make octopuses some of the ocean’s most mesmerising creatures.
They seem almost alien — and in a way, they are. Scientists believe that octopuses are so unique that they stand apart from nearly every other animal on Earth.
Octopuses belong to a group of animals called cephalopods, which also includes squids and cuttlefish. The word “cephalopod” means “head-foot,” which makes sense because their arms are attached directly to their head. They have no bones, which allows them to squeeze through the tiniest spaces — even holes no bigger than a coin. This boneless body is protected only by soft skin that can change texture and colour to match surroundings in seconds. Hidden inside special cells called chromatophores are tiny sacs of pigment that expand or shrink to create patterns. This ability is not just for show — it helps them camouflage from predators or startle enemies by flashing sudden bright colours.
Octopuses live in oceans all over the world, from shallow coral reefs to deep sea caves. Some are tiny, like the blue-ringed octopus, barely the size of a golf ball, while others, like the giant Pacific octopus, can stretch more than five metres from arm to arm. Despite their differences, they all share incredible intelligence.
Octopuses are known to solve puzzles, open jars, and even escape from tanks. In laboratories, they have been seen carrying coconut shells to use as portable shelters — a sign of tool use, which is extremely rare among non-human animals.
This intelligence comes from a remarkable brain. In fact, octopuses have three hearts and nine brains — one central brain and eight smaller ones, one in each arm. The arms can sense, taste, and even act semi-independently, helping the octopus explore and react quickly. When one arm touches food, it can pass the information to the others almost instantly. Because of this unusual nervous system, scientists think of octopuses not just as animals with a brain, but as creatures whose entire bodies think.
Their escape skills are legendary. Some aquariums have reported octopuses sneaking out of their tanks at night, crossing floors to reach other tanks, eating the fish inside, and returning to their own without leaving a trace. Others have been caught unscrewing jar lids or pulling plugs to drain tanks. It’s no wonder some researchers call them the “Houdinis of the sea.”
Octopuses also have fascinating defences. When threatened, they can release a cloud of ink to confuse predators and then dart away using jet propulsion — expelling water forcefully through a siphon. Their soft bodies make them fast and flexible, and some can even mimic the shapes and colours of other sea creatures. The mimic octopus, for example, can imitate the movements of a lionfish, a sea snake, or a flatfish, depending on which predator it faces.
Life for an octopus, however, is short but eventful. Most species live for only one or two years. After mating, a female lays thousands of eggs in a safe place and guards them tirelessly, often without eating. When the babies hatch, she dies soon after, having completed her life’s mission. The tiny hatchlings drift away, ready to begin their own secret lives in the sea.
Throughout history, humans have both feared and admired octopuses. Ancient sailors told stories of monstrous sea creatures with enormous tentacles capable of pulling ships underwater — myths that inspired legends like the kraken. In Japanese folklore, octopuses are featured in art and tales as mysterious, almost otherworldly beings. Today, they are studied not as monsters but as marvels — examples of evolution’s creativity.
Scientists are still uncovering more about octopuses. Recent studies suggest they can feel pain, recognise individual humans, and even remember past interactions. Some researchers believe that if evolution had taken a different path, octopuses might have developed forms of intelligence similar to humans — proof that complex thinking is not limited to animals with backbones.