Octopus Facts ~ Octopus FAQ

by Robert Cheney

in Octopus, Sea Life

What does the word octopus mean?
8 legs

How many species of octopuses are there?
Over 100

Is every octopus venomous?
Yes. The Blue-ringed octopus is the most venomous.

Where do octopuses live?
They live in dens, spaces under rocks, crevices on the sea floor, or holes they dig under large rocks.

What is the larges octopus?
Enteroctopus dofleini, also known as the Giant Pacific Octopus or North Pacific Giant Octopus is the largest species of Octopus with the heaviest ever found weighing in at 600 lbs.1  Not quite the giants that can sink ships but an eyeful if you happen to meet one in person.

Biggest Octopus in the World

Chameleon-like, giant Pacific octopuses can change their appearance to mimic rocks and highly patterned coral.
National Geographic Photograph by Bob Cranston—Animals Animals – Earth Scenes

What about the octopus beak?
The beak is the only hard part of an octopus and squid’s body. It is located on the lower side of the body. In the mouth is a radula, a toothed tongue for rasping. The beak is made of the same material, keratin, that a bird’s beak and our fingernails are made of. Octopuses use it to crush the crabs and mollusks that they feed on.

Do the octopus and squid have different types of beaks?
Yes.  The squid mainly feeds on soft bodies animals such as fish as well as other squids and needs a sharp cutting beak. While the octopus can and does eat fish (even small sharks), it feeds mainly on crabs (as well as other shelled inverts) and needs that short crushing beak.

Octopus and a squid beak

Squid beak (left) is for tearing. Octopus beak (right) is for crushing. Look like parrot beaks.

Octopus eye facts

  • They have 2 eyes with excellent vision .
  • They have rotating eyes.
  • They have an ability to align their eyes horizontal even though the body may be aligned at any angle.
  • They have no blind spot.
  • Their pupils are horizontal, while ours are round.
  • They are nearsighted and can’t see much past 8 feet.
  • They have polarized vision which allows them to see nearly invisible critters like jellyfish.

Octopus eye versus human eye
Octopus and human eyes are similar even though they developed on different paths. Each has a cornea, an iris, an accommodating lens, a fluid-filled vitreous humor, a retina, and so forth.

Octopus eyes focus like a camera with the lens moving in or out while our eyes use muscles to squeeze the lens to focus. The octopus eye, like other invertebrate eyes, develops as an invagination, or in-pocketing, of the skin. Human eyes develop as extensions of the brain. Here is a more detailed explanation of the difference.

What about octopus ink?
The ink is concentrated melanin, the same pigment that our makes hair and skin dark. Most octopuses have the ability to squirt this inky pigment, but not all. The ink also contains a compound called tyrosinase that irritates the eyes and sense of smell of the predator.

Are there any fresh water octopuses?
No, they are strictly salt water animals.

What is the best octopus book?
Octopus: The Ocean’s Intelligent Invertebrate is filled with pictures an in-depth knowledge on the octopus.

Octopus Book

The Best Book on Octopus

About the octopus brain
Only mammals and birds have more complex brains than that of the octopus. Octopuses have excellent memories, have played with objects, unscrewed jars to get to the crab inside. Their brain has folds, another indication of complexity. They can be left-eyed or right-eyed like in humans with their hand preferences.

What is our common ancestor with the octopus?
600 million years ago , we were both a little wormlike creature with eyespots.

How many hearts does the octopus have?

Why do they have 3 hearts?
Basically, when you have 8 legs you need extra blood flow, thus having more than one heart is necessary.  Octopuses have three hearts. Two pump blood through each of the two gills, while the third pumps blood through the body.

Octopus anatomy
Here is visual on octopus anatomy:

octopus anatomy

Octopus Anatomy

What do octopus eat?
Crabs, clams, snails, small fish, and even other octopuses.

How much food will an octopus eat throughout its lifetime?
Multiply its weight by 3 and that’s roughly how much its eaten during its lifetime.

What is the plural of octopus?
Octopuses. Octopi is wrong, although generally accepted these days.

Are there any endangered octopuses?
No, there are none on the ICUN Red List.

What is octopus life cycle?
They start as eggs. Hatch after a few months, depending on water temperature. Hatched larva swim to the surface and float around eating everything they can until they are heavy enough to sink to the bottom where they live life as  an octopus and continue growing their entire lives.

Can octopus be kept as pets?
Yes, but read this guide.

Do people go octopus fishing?
Most definitely:

Are octopuses smart?
Yes they are. Only mammals and birds are smarter.

Octopus life expectancy
6 months for smaller ones and up to 5 years for larger ones like the Giant Pacific octopus. Breeding is what does them in as they stop eating after breeding and essentially starve to death.

Do octopus have teeth?
Yes, they have teeth on their tongue, inside their mouth and on on their suckers.

What is the smallest octopus?
The Octopus Wolfi is half an inch long and weighs 1 gram.

What is the most famous octopus?
Paul the Octopus correctly predicted the winner of all 7 German matches during the 2010 World Cup. He  also correctly predicted Spain as the overall winner.

What is the nutritional value of octopuses?
Octopus is common in some types of cuisine like Japanese, Mediterranean and Polynesian. Octopus is a lean, low calorie seafood that is a good source of calcium, potassium, phosphorus and selenium. It provides several important vitamins including vitamin C, vitamin A and several B vitamins, as well as some omega-3 fatty acids.

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{ 4 comments… read them below or add one }

Sizwe Maeggz Ndwandwe August 30, 2014 at 9:09 am

Woooooow this is an amazing animal


hoppe mhlanga May 16, 2013 at 6:20 pm

what an amazing sea-creature


Margaret Reardon April 10, 2013 at 12:13 pm

How many suckers does an octopus have on its arms and tentacles?


Tionalynell April 10, 2013 at 6:58 pm

The Giant Pacific Octopus has around 2000 suckers. So divide that by 8 and it’s roughly 250 per arm. Of course this a large species so other smaller octopuses will have less in proportion.


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