Octopus under the sea surrounded by coral — Octopus under the sea | Photo by Adam Hanlon

Octopuses are some of the ocean’s most fascinating, weird, beautiful and misunderstood creatures. The common octopus, found in the Canary Islands, is particularly notable for its adaptability, impressive physical attributes, and unique ability to move quickly and fit into small spaces. With their alien-like appearance, exceptional intelligence, and astonishing survival skills, it’s no wonder they’ve captivated marine biologists and ocean lovers alike. The diversity and uniqueness of various octopus species, such as the Wonderpus octopus, Coconut octopus, and blue ringed octopus, add to their intrigue. In this blog, we’ll dive into 15 amazing octopus facts that reveal just how strange, smart, and spectacular these eight-armed animals really are.

Whether you’re curious about how long they live, what they eat, or how they escape predators, this article is packed with fun facts about octopuses that will deepen your appreciation for these marine marvels.

1. Octopuses Have Three Hearts

Octopuses have a unique circulatory system with three hearts. Two pump blood to the gills, while the third heart is responsible for circulating oxygen-rich blood to the organs. Interestingly, the heart that supplies the body stops beating during swimming, which is why octopuses often prefer crawling to conserve energy.

2. Their Blood Is Blue

Unlike mammals, octopus blood is blue due to the presence of hemocyanin, a copper-rich protein that binds with oxygen. Hemocyanin is more efficient in cold, low-oxygen environments, helping octopuses survive in the deep sea. The deep sea octopus, for instance, thrives in these extreme conditions due to the efficiency of hemocyanin.

3. Octopuses Can Change Color Instantly

With specialised cells called chromatophores, octopuses can change their skin color and texture in milliseconds. They have some of the weirdest adaptations in the world. With their eight arms, they can enhance their camouflage and communication abilities by manipulating their surroundings and body posture. These specialised cells allow them to use this ability for camouflage, communication, and even mimicry—some species can imitate venomous sea creatures like lionfish or sea snakes.

octopuses can change their colour | Photo by Jodi Jacobson

4. They’re Masters of Escape

Octopuses are famous escape artists. They utilize a special muscular tube called a siphon to propel themselves by blasting water, allowing them to achieve high speeds while swimming backward to escape predators. With no bones, they can squeeze through small openings as tiny as their beaks. Stories abound of octopuses breaking out of aquariums, crawling across floors, and sneaking into other tanks for a midnight snack.

an octopus swimming in the ocean — Octopuses use a siphon to propel themselves | Via Getty Images

5. Octopuses Have Nine Brains

Octopuses were mentioned in the article about the animals with the biggest brain for a reason. They have a central brain and a mini-brain in each arm, allowing for decentralized control. About two-thirds of an octopus’s neurons are found in its arms, enabling each arm to touch, taste, and even operate semi-independently, helping the octopus multitask like no other marine animal. An experiment demonstrated their advanced recognition skills, where octopuses could differentiate between a 'nice' keeper who fed them and another who used a bristly stick to touch them.

6. They Use Tools

Tool use is rare in the animal kingdom, but octopuses are known to carry coconut shells for shelter, arrange rocks around dens, and use discarded shells to defend themselves. The coconut octopus, in particular, uses a coconut shell as a portable shelter and tool, showcasing its intelligence and problem-solving skills. This level of problem-solving puts them on par with birds and primates.

7. They Can Regrow Lost Arms

Lose an arm? No problem. Octopuses can regenerate their powerful arms completely, including nerves and muscle structure. The process takes only a few months and doesn’t leave a scar.

an octopus swimming underwater — ctopuses can regenerate their arms | Photo by Rich Carey

8. Octopuses Have Beaks Like Parrots

Octopuses use a sharp beak—similar in structure to a parrot’s—to break open hard-shelled prey like clams. The beak, made of chitin, is their only hard body part and is located at the center of their arms.

two parts of an octopus mouth — Octopus beak | Photo by Ian Redding

9. They Shoot Ink to Escape Predators

When threatened, octopuses release a burst of inky fluid that obscures a predator’s view. Some ink contains a compound that numbs a predator’s sense of smell, making the octopus even harder to track.

an octopus inking at the bottom of the sea — Common Octopus inking | Photo by Alexey Masliy

10. Octopuses Are Short-Lived but Brilliant

Despite lifespans of just 1–5 years, octopuses show remarkable intelligence. Similar to dolphins, octopuses exhibit advanced cognitive abilities and tool use, highlighting their problem-solving skills. Research conducted by biologists at the Seattle Aquarium has demonstrated their impressive recognition abilities. They can solve mazes, open jars, recognize individual humans, and even use observational learning—an ability few animals possess.

11. They Can Taste With Their Arms

Octopus arms are lined with sensors that detect chemical cues in the water. This means they can crawl along the ocean floor while using their arms to “taste” and “touch” their surroundings simultaneously—a huge advantage when hunting in dark or murky waters.

12. Some Octopuses Walk on Two Arms

Certain species, like the coconut octopus, exhibit bipedal locomotion. Octopuses use a muscular tube called a siphon to propel themselves backwards through the water at high speeds, aiding in their movement and navigation. The mimic octopus is another remarkable creature known for its extraordinary ability to imitate other animals for protection. They walk on two arms while disguising themselves with shells or coconut husks—a rare behavior among invertebrates.

Coconut octopus exhibit bipedal locomotion | Photo Dive Ivanov

13. Female Octopuses Die After Laying Eggs

Once eggs are laid, the female enters a brooding period during which she doesn’t eat. She spends weeks or months guarding and oxygenating her eggs until they hatch. Shortly after the eggs hatch, she dies, a sacrifice for the next generation.

14. The Giant Pacific Octopus Is the Largest Species

This species can reach lengths of over 16 feet (5 meters) and weigh more than 100 pounds (45 kg). Despite pressures from human activities, many octopus populations are thriving due to their adaptability and the reduction of larger predator fish in the ecosystem. It uses its massive size and camouflage abilities to ambush prey like crabs, fish, and even small sharks.

15. Octopuses Might Dream

Studies have observed octopuses displaying rapid eye movement and color changes during rest—indicators of REM-like sleep. When the animal dies, its blood changes color, highlighting the unique physiology of octopuses. Scientists speculate they may be replaying memories or processing information.

16. They Can Squeeze Into Incredibly Small Spaces

Because they have no skeleton, octopuses can fit through spaces as small as their beak, often less than an inch wide. They construct their dens using rocks and create a 'rock door' that pulls closed when they are inside for protection. They use a specific muscular structure on their body called a ‘siphon’ to swim backwards at impressive speeds, making them nearly impossible to contain and perfect for exploring tight crevices.

an octopus hiding on a shell — Octopuses can fit through spaces as small as their beak | Via Getty Images

17. They Communicate Through Color

Specialised cells called chromatophores allow octopuses to change color for communication. Besides camouflage, color changes are also a form of communication. Octopuses may flash white when agitated or show dark, pulsating colors when warning off threats or asserting dominance.

18. They Have Complex Nervous Systems

Octopuses have one of the most intricate nervous systems in the invertebrate world, with over 500 million neurons—more than some small mammals. About two-thirds of these neurons are found in their arms, explaining their independent function.

19. Some Species Are Venomous

While most octopuses are harmless, species like the blue-ringed octopus carry venom potent enough to paralyze humans. Despite its small size, it's one of the most dangerous animals in the ocean and one of the deadliest animals in Australia.

blue ringed octopus swimming underwater — The blue-ringed octopus carry venom potent enough to paralyze humans | Via Getty Images

20. They're Ecological Indicators

Because of their sensitivity to pollution and temperature changes, octopuses are considered bioindicators. Over fishing significantly impacts marine ecosystems, and conservation efforts are crucial to combat this issue and ensure the survival of various marine species. Increasing ocean acidity, influenced by climate change, affects their ability to survive by disrupting their oxygen circulation due to their sensitivity to changes in acidity. Studying their behavior and health helps scientists monitor ocean ecosystems.

Octopuses in Culture and the Collective Imagination

Octopuses have captivated human imagination for centuries, appearing in myths, legends, literature, and modern media. A common misconception is that the plural of 'octopus' is 'octopi,' but the correct pluralization in English is 'octopuses.' In ancient maritime folklore, the Kraken, a giant octopus-like sea monster, was said to rise from the depths and drag entire ships under with its enormous tentacles. This myth, originating in Norse and later Mediterranean traditions, reflects both awe and fear of the unknown ocean and its strange inhabitants. Beyond folklore, octopuses often symbolize mystery, transformation, and intelligence in art and storytelling. The word ‘octopus’ itself has Greek origins, with historical perspectives including Aristotle’s view on octopuses as documented in ancient Greek philosophy. In modern times, their alien-like appearance and remarkable abilities have inspired science fiction, most notably the extraterrestrial beings in the film Arrival, whose design and communication methods were directly influenced by octopus morphology and intelligence. From Paul the Octopus accurately predicting World Cup matches to their recurring presence in tattoos, cartoons, and logos, these cephalopods have become enduring icons in global culture, blending science, symbolism, and the deep sea mystique.

An AI generated image of a kraken attacking a ship — In ancient maritime folklore, the Kraken, a giant octopus-like sea monster

The Ocean Icons

Whether it’s their alien anatomy, next-level intelligence, or strange behaviors, there’s no denying that octopuses are some of the most extraordinary animals on Earth. Conservation efforts to protect octopuses and their habitats are essential to ensure their survival. They challenge our understanding of consciousness, survival, and evolution in ways few other animals do.

Marine species, including octopuses, face significant challenges due to threats like overfishing and habitat destruction, making conservation efforts crucial for their survival.

Meta Title: 15 Amazing Octopus Facts That Will Blow Your Mind Meta Description: Discover 15 amazing octopus facts! From blue blood to three hearts and tool use, learn the most interesting facts about octopuses in this deep dive into their bizarre world.

20 Amazing Octopus Facts That Will Blow Your Mind