15 Interesting Facts about the Octopus You Need to Know!


15 Interesting Facts about the Octopus

Polbo / Octopus by Feans cc2.0

An octopus is a sea creature with eight arms, hence its name, because in Greek, okto means eight. It is related to the squid and the cuttlefish, and has roughly 300 known species found all over the world. Do you want to know more about this amazing animal? Here are fifteen interesting facts about the octopus.

1. The plural of octopus is octopuses.

pair of octopuses

According to the Oxford Dictionary, the most correct and most widely accepted plural form of “octopus” is “octopuses”. This is because it comes from the Greek word oktōpous — and so it should be expressed in plural form as a Greek word, as well, with an -es added at the end. “Octopodes” is also accepted as a plural. As for “octopi”, scratch it. After all, you wouldn’t say hippopotami as the plural for hippopotamus, would you?

2. The giant Pacific octopus is the largest octopus in the world.

giant pacific octopus
Giant Pacific Octopus by Karen cc2.0

The largest giant Pacific octopus ever recorded reached up to 30 feet (9 meters) across and weighed 600 pounds (272 kilograms). On average, however, they’re around 16 feet (5 meters) long and weigh about 110 pounds (50 kilograms), making it larger than any other octopus. It is so big, in fact, that it can eat sharks, being able to break a shark’s spine with its powerful arms.

The Atlantic pygmy octopus, in contrast, weighs only an ounce (28 grams) and has arms about 3 inches (8 centimeters) long, and scientists say it’s not even the smallest octopus out there.

3. An octopus has three hearts.

It has one large heart and two smaller ones. The two smaller ones are close to the gills and enrich the blood with oxygen before transferring it to the large heart. The large heart then pumps this refreshed blood to the rest of the octopus’ body.

3 hearts

4. Octopuses have blue blood.

Nope, they’re not royalty. They literally have blue blood. This is because their blood is not iron-based like ours, but copper-based, the copper being more efficient in transporting oxygen in a cold, low-oxygen environment.

5. Octopuses die young.

Dead octopus
dead octopus by Eugene Peretz cc2.0

Some scientists believe that an octopus’ short lifespan is its only flaw. Sadly, an octopus can only live from 1 to 5 years. After mating, males wander off and die quietly. Females, on the other hand, die after their eggs hatch. It’s almost as if they have a switch inside them which turns off as soon as their eggs hatch, causing them to die one cell at a time at a rapid pace.

6. An octopus’ brain is as large as a bird’s.

ocotpus brain

Octopuses don’t have big brains. In fact, they have bird brains. In spite of this, though, the octopus is considered one of the most intelligent animals in the world. In the wild, octopuses can use tools in order to open shellfish or to hide themselves. In captivity, they have shown the ability to solve problems such as opening a bottle to get the food inside.

Oh, and by the way, the brain of an octopus doesn’t do all the thinking for it. In fact, about two-thirds of an octopus’ brain cells, or neurons, are distributed among its arms. In this way, an octopus can perform several tasks at the same time. This is also why a detached octopus arm can still react to pain.

7. Octopuses eat mostly shellfish.

Veined Octopus -Amphioctopus Marginatus eating a Crab
Veined Octopus – Amphioctopus marginatus eating a Crab. By prilfish cc2.0

The typical diet of an octopus consists of crabs, prawns and mollusks. How do they get through the hard shell? They can break it apart using their strong beaks, or drill a hole into the shell and then slurp the soft parts inside.

8. Octopuses have gardens.

Octopus shell
Octopus marginatus hiding between two shells from East Timor. Photo by Nick Hobgood cc3.0

It has been observed in captivity that octopuses like shiny objects. In the wild, they travel across the ocean floor picking up shiny objects, and then arranging them into a collection called an “octopus garden”.

9. An octopus can regrow its arms.

octopus arms - regenerate

Several animals can regrow lost limbs, like lizards, for example, and starfish. The octopus has this ability, too. It can detach an arm in order to distract predators, and then grow a new one in its place, which is quite a luxury when you have eight arms.

10. Octopuses can squeeze in and out of tight spaces.

Octopuses are among the most flexible animals on earth. They don’t have skeletons. In fact, the only hard part of their bodies is their beak, which is made of cartilage and located inside their heads. This means they can squeeze anywhere their heads can slip through, and they will, since they would rather flee at the hint of danger than put up a fight. A large octopus has even been known to slip inside a beer bottle. Amazing, isn’t it? That is, unless you’re the one in charge of making sure these creatures don’t escape.

11. Octopuses have strong suckers.

octopus suckers

Octopuses have large suckers on their arms, made of tiny, complex muscles, making them far more elaborate than mere suction cups. These suckers can apply a great deal of pressure — enough to tear flesh. They can also lift heavy weights. In the case of the giant Pacific octopus, one sucker can lift an object as heavy as 35 pounds (16 kilograms)!

12. The mimic octopus can imitate an unknown number of animals.

mimic octopus

Think chameleons are the masters of disguise? Think again. Octopuses can not only change color, but can also change form in order to truly imitate another creature or object, in so doing efficiently catching prey or escaping predators. And the mimic octopus is the best of them all. It can look like a rock, a sea snake, a sting-ray, a flounder, a different species of octopus, a jellyfish, a crab, a lionfish… the list just goes on and on.

13. The blue-ringed octopus can kill with one bite.

blue ringed

The blue-ringed octopus may look pretty and docile, but be warned. Even though it is less than 8 inches (20 centimeters) long, this octopus is one of the deadliest animals — its venom is toxic enough to kill a human being. In fact, one blue-ringed octopus carries enough venom to kill as many as twenty-six humans, all within minutes. The venom consists of various toxins, one of which is the same found in poison dart frogs and pufferfish. What makes the venom of the blue-ringed octopus even more dangerous is that there is no antivenom available yet, plus, the bite is often painless, so victims do not realize they have been bitten until it is too late.

Blue-ringed octopus are featured in the following books:
25 Most Deadly Animals in the World
25 of the Most Poisonous Animals in the World!.
Octopus – Alien of the Deep

14. There is such a thing as a dumbo octopus.

grimpoteuthis discoveryi dumbo octopus
One of the rare finned octopods known as “Dumbos” collected on the summer 2009 MAR-ECO cruise. Image credit: Mike Vecchione, NOAA

You’ve probably heard of Dumbo, Disney’s flying elephant. But have you heard of the dumbo octopus? Now you have. The dumbo octopus is a small octopus that hovers above the ocean floor, its tentacles webbed so that they spread out like an umbrella. How did it get its name? It is the only octopus with large fins on the sides of its head, which look just like ears.

Dumbo octopus is discussed in several books from our Amazing Animals Series…
25 Weirdest Animals in the World
Alien of the Deep – the Octopus!
25 Deep Sea Creatures

15. The vampire squid is more closely related to octopuses.

Vampire Squid
Adult vampire squid (Vampyroteuthis infernalis). By Citron / CC-BY-SA-3.0

The vampire squid may be called a squid but, in reality, it is more closely related to octopuses, being grouped together with them in the superorder Octopodiformes. Like an octopus, it has eight arms with webbing in between, making it look like it is wearing a cloak. Combined with this dark cloak, its eyes (which sometimes glow red) make it look like a vampire in the depths of the ocean. When threatened, the vampire squid has a special ability. Instead of shooting ink, it puts on a light show, dazzling its opponent.

Vampire Squid are featured in the following books:
25 Deep Sea Creatures
25 Weirdest Animals in the World

Want more? Visit:
Top 10 Examples of Awesomely Interesting Octopus Behavior!
The Octopus – Alien of the Deep!
10 Dumbo Octopus Facts & Adaptations!
The Amazing Octopus – Questions Answered!
Octopus Quiz!

What do you know?

Think you remember what you’ve read? Try out the Octopus Quiz!


15 Facts About The Octopus.



To view the complete list of sources, please click here.


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  2. Ten Curious Facts About Octopuses

    Octopuses, an inspiration for monsters throughout history, get a fresh look through a new book that dives deep into the creatures’ mysterious lives
    Octopuses, those whip-smart but bizarre cephalopods, seem to embody everything creepy and mysterious about the sea–the thought of their soft squishy bodies lurking in the oceans’ dark reaches has inspired monsters ranging from the Kraken to the Caribbean Lusca. Their otherworldly forms, heightened by unfurling arms, find their way into more modern monsters and villains too–think Disney’s sea witch Ursula or Spider-Man’s Doc Oc. And don’t forget the octopus-themed horror movies!

    1) Octopuses are waaay old. The oldest known octopus fossil belongs to an animal that lived some 296 million years ago, during the Carboniferous period.

    2) Octopuses have three hearts. Two of the hearts work exclusively to move blood beyond the animal’s gills, while the third keeps circulation flowing for the organs.

    3) The plural of octopus is octopuses. The word “octopus” comes from the Greek, októpus, meaning “eight foot.”
    4) Octopus arms have a mind of their own. Two-thirds of an octopus’ neurons reside in its arms, not its head.
    5) Octopus ink doesn’t just hide the animal. The ink also physically harms enemies. It contains a compound called tyrosinase, which, in humans, helps to control the production of the natural pigment melanin. But when sprayed in a predator’s eyes, tyrosinase causes a blinding irritation.
    6) Octopuses have blue blood. To survive in the deep ocean, octopuses evolved a copper rather than iron-based blood called hemocyanin, which turns its blood blue. This copper base is more efficient at transporting oxygen than hemoglobin when water temperature is very low and not much oxygen is around.


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