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Home › Sea Life › Marine Animals › Invertebrate › Molluscs › Octopus

Facts and Information about Octopus

[Phylum: Mollusca] [Class: Cephalopoda] [Order: Octopoda] [Scientific Name: Octopus vulgaris]

The common octopus (Octopus vulgaris) is a marine mollusk belonging to the biological order Octopoda. There are at least three hundred (300) different types of octopus still in existence today.

This section contains a collection of fun and interesting facts about octopuses, including where they live, what they eat, and how these eight-limbed mollusks reproduce.

Common Octopus Habitats and Distribution

Check out our list of marine molluscs and you'll only find a few that can survive in every ocean.

Yet, octopuses (also called octopodes or octopi), are found in all oceans worldwide, especially shallow marine habitats and tide pools in:

• South East Asia
• Europe
• United Kingdom

Like many shell-less cephalopods, most types of octopuses are pelagic creatures. Hence, some drift with the natural movement of water currents close to the surfaces of major seas and oceans.

Whereas other octopus species are demersal, such as the big blue octopus (Octopus cyanea), found living around the coral reefs, crevices, dens, and caves at intertidal zones of the Pacific and Indian oceans.

Plus, some of the deep sea octopus types have adapted to life in cold water habitats. For example, the spoonarm octopus (Bathypolypus arcticus) can withstand depths approaching one thousand metres (3,300 feet).

Even more astounding is the tiny benthic octopus (Vulcanoctopus hydrothermalis) living at the abyssal depths of 2,000 metres (6,600 feet).

Interesting Fact: Out of all octopus species, only the cirrate (ear-like fins) Dumbo octopus (Grimpoteuthis) has been photographed within the oceanic trenches of the hadopelagic zone, at a staggering 6,957 metres below the surface (22,825 feet).

Characteristics of Octopuses

The octopus phylum is mollusk, meaning they are one of the typical examples of oceanic invertebrates that have a soft body (called a mantle), and a cephalopod that displays (bilateral symmetry).

It is easy to identify most octopus species by the rounded body and bulging eyes. They also have eight dangling appendages - not tentacles!

In case you were wondering:

Despite the myths and fables, there is no giant lake octopus! The unique features of an octopus anatomy means it cannot survive in freshwater.

Intelligence, Disguise, and Trickery

They are incredible creatures of underwater movement and disguise, with unrivalled intelligence for their trickery and mesmerising acts of mimicry.

An octopus can perform amazing feats of escapism and illusion that simply defies belief. They can hide inside, and escape through, tight spaces and holes that measure 10% of their body size. They have mastered impersonation, imitation, camouflage, and deception.

They can change their body colours and structural appearance, in seconds! They mimic their natural surroundings transforming themselves to invisibility, and elude capture as they jettison a cloudburst of smoky blackish ink.

But wait - there's more:

Their extra-large brain makes them likely contenders for the most intelligent invertebrate. It is almost certain that they have both short-term and long-term memory capabilities. In fact, evidence suggests their memory storage is so advanced that they use it to solve physical and pictorial problems underwater.

Curiously, the adults fail to pass down this amazing animal brainpower and behavioural intellect to newborns. As a consequence, there is very little direct contact between adult and baby octopus fry.

Octopus Size and Weight

The overall size of the common octopus (Octopus vulgaris) varies between thirty and ninety centimetres long (12 to 36 inches). They can weigh anywhere between three (3) and ten (10) kilograms (6 to 22 pounds).

Enteroctopus dofleini is by far the largest octopus, often growing to five metres long (16 feet) and weighing up to fifty kilograms (110 pounds.

Whereas, Octopus wolfi is the smallest measuring around 2.5 centimetres long (one inch) and weighing less than one gram.

Fun Fact: Octopodes meaning the plural of their name, refers to a "consortium of octopuses" as being the correct label for a large group. Octopi also rank as the most intelligent invertebrate in any salt-water ocean kingdom.

What Do Octopus Eat?

After capturing their prey, most species of octopus return to the safety of their den to eat it - or store it. Thus, it's not unusual to find a hoard of uneaten food rotting inside their lair.

Nonetheless, the daily source of food for these predatory, bottom-dwelling carnivores often includes a combination of:

• Copepods (including amphipods and isopods)
• Crabs (especially spider crabs)
• Crustaceans
• Echinoderms (e.g. sea urchins)
• Lobsters
• Other cephalopod species
• Polychaete worms
• Prawns
• Sea birds
• Slow-moving fish
• Small sharks
• Small bivalve molluscs (clams, scallops, whelks)

For the most part, they are a solitary animal (outside the mating season). But, studies suggest that some octopus hunt together in small groups.

After dropping down on a defenceless animal - and enveloping it with their arms - they pull the captured prey into their mouth and use their powerful jaws to crush and swallow it.

Different Types of Octopus

10 Fun Facts about Octopus

1. The common octopus vulgaris has a large central brain (including 8 "mini-brains" to help control individual movement in each arm).
2. There is no denying that octopus body parts are unique. These soft-bodied mollusks have three blood-pumping hearts and blue-coloured blood.
3. New-born octopus larvae float with microscopic planktonic organisms at the surface for three or four weeks before it can return to the seafloor.
4. The small-egg Caribbean pygmy octopus (Octopus joubini) lives inside an empty clam shell (after using its radula to bore its way through).
5. Using their large bulbous head for propulsion and movement, octopi are efficient swimmers and many use their muscular funnel (siphon) to swim backwards at great speed.
6. Octopodes have extremely acute sight, touch, and taste sensory organs. But, they are deaf and cannot hear normal sounds underwater.
7. Females often eat the male after copulation and they typically lay more than 200,000 eggs over a two week period.
8. When threatened, they usually change to a white body colouring and some octopus species squirt black ink when trying to flee their predators.
9. The word "octopus" means eight-footed (or eight-armed) in Greek. As a matter of fact, an octopus has 8 appendages (limbs) that consist of 6 arms (with suction cups on the bottom), 2 legs, and no tentacles.
10. They are probably the most intelligent of all invertebrate animals and they can distinguish between shapes and patterns.

Octopus Vulgaris Taxonomy

For classification purposes, there are two (2) suborders in the order octopoda. Incirrina (also Incirrata) is the most familiar and Cirrina (also Cirrata) is the lesser-known of the two divisions.

Cirrate octopus have two fins shaped like ears and an internal shell for support, especially when swimming. Hence, members of this suborder have some difficulty squeezing through small spaces.

Scuba Divers Beware!

The blue-ringed octopus is the most poisonous of all octopuses. The venomous saliva from this deadly creature can be fatal for humans. There is currently no antivenom available, so octopus bite treatment needs to be swift.

Pro Tip: If you're wondering what animal kills the most humans in the world, it's definitely not any of the common octopus species!

How Do Octopus Reproduce?

Living in fringing reefs and rock pile burrows means the female can lay eggs in areas with some protection. But in the end, octopus reproduction and mating rituals actually contribute to the premature death of both parents.

Here's the thing...

The male uses a special arm to deliver spermatophores into the mantle cavity of the female. Following that, he will die shortly after.

It gets worse. The female stops eating for several weeks after laying the eggs. Her endocrine system has a genetic program (aka cellular suicide) that kills her when the octopus eggs (up to 400,000) have hatched into fry.

After the eggs have hatched, small octopus larvae drift in clouds of plankton, feeding on zooplankton as they start growing.

Threats and Predators

The average life expectancy for most types of octopus is short, around three (3) years. In fact, some of the warm water bottom-dwellers only have a six month existence.

Whereas, the lifespan of the North Pacific giant octopus (Enteroctopus dofleini) is usually much longer, up to five (5) years.

Even in healthy marine ecosystems, there are many ferocious ambush predators that eat octopus as a regular food source, especially:

• Conger eels
• Marine mammals (e.g. dolphins, seals)
• Moray eels
• Sharks

Important: The IUCN Red List of Threatened Species is a comprehensive source of information about the global conservation status of animals, fungi, and plants. Currently, the IUCN lists the common octopus (Octopus vulgaris) as Least Concern (LC).

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