The Blue-Ringed Octopus

Let’s get into the Aussie English Fact today, where I wanted to talk to you about what kind of animal? The blue ringed octopus, ok? So, today’s fact is about one of Australia’s deadliest animals. The unsuspecting, enigmatic and petite blue ring octopus. A group of four species of octopus, the blue ring octopus is a marine animal, it is a cephalopod, which are a group of eight legged mollusks and they include the octopus, as well as squid and cuttlefish and nautilus, nautilus as well.

So, these guys live in intertidal zones and reefs surrounding Australia, but they are also found all throughout the Pacific and Indian oceans as far North as Japan and as far South as Australia. So, the blue-ringed octopus is a tiny and docile little critter, only about 12 to 20 centimetres in length. So, they can generally fit in your hand. They’re active at night, they are nocturnal, and they feed primarily on crabs, hermit crabs, shrimp and any other crustaceans they can get their tiny little tentacles onto.

These guys only live for a very short period of time of about two years and spend much of that time hiding in crevices, whilst displaying effective camouflage patterns with their dermal chromatophores or cells. In other words, they camouflage themselves, they hide themselves with their skin cells that can mimic colour and texture of their surroundings. So, when provoked, they quickly change colour and they become a bright yellow with each of their 50 to 60 iridescent blue rings flashing as a warning signal: ”don’t eat me! Go away! I’m poisonous!”.

The octopus produces venom containing a number of different chemicals, but of which the most potent and deadly is a chemical called Tetrodotoxin. Interestingly, this toxin is not produced by the octopus itself, but instead, it is produced by bacteria that live in the octopus’s saliva so that when any prey item is bitten by the octopus, the toxin is injected and within moments the defenceless victim is rendered paralysed and it’s more easily and safely consumed by the octopus. You know, you don’t want those crab pincers chopping off your little tentacles.

If you’re an unlucky human fossicking around the rocky shore in Australia, lifting up rocks, picking up shells or putting your hands in crevices where they don’t belong, you might receive a painless little nip from a frightened octopus trying to defend itself. One of these octopus carries enough venom to kill 26 adult humans, within only a few minutes once the venom has paralysed the diaphragm and you suffocate because you can’t breathe.

The good news is, you’ll survive just fine as long as you’re aware that you’ve been bitten and as long as someone that you’re with can do mouth to mouth, they can do CPR on you and help you breathe until ambulances arrive. Once the ambulance arrives, it will take you to a nearby hospital and put you on a medical ventilator to breathe for you until the venom is metabolised by your body and disappears, usually within about 24 hours. More good news, is that despite its deadly abilities, only three people are known to have died from blue ring octopus bites, two In Australia and a one in Singapore.

Many more have come close to death, but live to tell the tale. So, the moral of the story: make sure that you keep your hands to yourself at the beach. Don’t put them in any dark crevices, in rock pools, where they don’t belong and you’re intruding into the homes of these little octopus and also make sure you empty out any shells that you pick up and want to put in your pocket.


A crab – a crustacean, found chiefly on seashores, with a broad carapace, stalked eyes, and five pairs of legs, the first pair of which are modified as pincers.

A crevice – a narrow opening or fissure, especially in a rock or wall.

A critter – a living creature; an animal.

A crustacean – an arthropod of the large, mainly aquatic group Crustacea, such as a crab, lobster, shrimp, or barnacle.

A cuttlefish – a swimming marine mollusk that resembles a broad-bodied squid, having eight arms and two long tentacles that are used for grabbing prey. Its internal skeleton is the familiar cuttlebone, which it uses for adjusting buoyancy.

A hermit crab – a crab with a soft asymmetrical abdomen, which lives in a cast-off mollusk shell for protection. In several kinds the shell becomes covered with sponges, sea anemones, or bryozoans.

A medical ventilator – an appliance for artificial respiration; a respirator.

A mollusk – an invertebrate of a large phylum which includes snails, slugs, mussels, and octopuses. They have a soft unsegmented body and live in aquatic or damp habitats, and most kinds have an external calcareous shell.

A nautilus – a cephalopod mollusk with a light external spiral shell and numerous short tentacles around the mouth.

A nip – a small bite.

A pincer – a front claw of a lobster, crab, or similar crustacean.

A reef – a ridge of jagged rock, coral, or sand just above or below the surface of the sea.

A shrimp – a small free-swimming crustacean with an elongated body, typically marine and frequently of commercial importance as food.

A squid – an elongated, fast-swimming cephalopod mollusc with eight arms and two long tentacles, typically able to change colour.

A tentacle – a slender, flexible limb or appendage in an animal, especially around the mouth of an invertebrate, used for grasping or moving about, or bearing sense organs.

A warning signal – a sign used to warn of danger.

An ability possession of the means or skill to do something.

An ambulance – a vehicle equipped for taking sick or injured people to and from hospital, especially in emergencies.

An intertidal zone – the area of the foreshore and seabed that is exposed to the air at low tide and submerged at high tide, ie the area between tide marks.

Bacteria – a member of a large group of unicellular microorganisms which have cell walls but lack organelles and an organized nucleus, including some which can cause disease.

Camouflage hide or disguise the presence of (a person, animal, or object) by means of camouflage.

Cephalopod an active predatory mollusk of the large class Cephalopoda, such as an octopus or squid.

Chop ST off – remove a part of ST by chopping.

Come close to death – nearly die.

Consume ST – eat or drink ST; use up a resource.

CPR short for cardiopulmonary resuscitation: a medical procedure involving repeated cycles of compression of the chest and artificial respiration, performed to maintain blood circulation and oxygenation in a person who has suffered cardiac arrest.

Deadly – causing or able to cause death.

Defenceless without defence or protection; totally vulnerable.

Dermal cells – a thin layer of cells covering the soft parts of a plant.

Dermal chromatophores pigment-containing and light-reflecting cells, or groups of cells, found in a wide range of animals including amphibians, fish, reptiles, crustaceans and cephalopods.

Diaphragm a dome-shaped muscular partition separating the thorax from the abdomen in mammals. It plays a major role in breathing, as its contraction increases the volume of the thorax and so inflates the lungs.

Docile ready to accept control or instruction; submissive.

Enigmatic difficult to interpret or understand; mysterious.

Feed on ST – consume ST as food.

Fossick – rummage; search.

Inject ST – introduce (a liquid, especially a drug or vaccine) into the body with a syringe.

Intrude (into ST) – put oneself deliberately into a place or situation where one is unwelcome or uninvited.

Iridescent – showing luminous colours that seem to change when seen from different angles.

Keep your hands to yourself – don’t touch anything.

Live to tell the tale – survive a dangerous experience and be able to tell others about it.

Metabolise ST – (of the body or an organ) process (a substance) by metabolism.

Mimic ST – copy or imitate ST.

Mouth to mouth – denoting a method of artificial respiration in which a person breathes into an unconscious patient’s lungs through their mouth.

Nocturnal – (of an animal) active at night.

Painless – not causing or suffering physical pain.

Petite – small.

Poisonous (of a substance or plant) causing or capable of causing death or illness if taken into the body.

Potent – having great power, influence, or effect.

Provoke ST – stimulate or incite (someone) to do or feel something, especially by arousing anger in them.

Rendered paralysed – cause ST to be unable to move.

Rocky – consisting or full of rock or rocks.

Suffocate – die or cause to die from lack of air or inability to breathe.

The moral of the story – the lesson you should learn from this story.

Unlucky – unfortunate.

Unsuspecting – (of a person or animal) not aware of the presence of danger; feeling no suspicion.