The blue-ringed octopus: small, alive and deadly (2023)

Blue-ringed octopuses are undeniably impressive. When alarmed, these animals display the eponymous iridescent blue rings covering their bodies and arms.

But their adorable small size and instagrammable looks are deceiving: blue-ringed octopuses are among the most venomous creatures in the oceans.

What is a blue-ringed octopus and where can you find it?

Blue-ringed octopuses are a group of highly venomous cephalopods.

These small squids have been found in the Pacific and Indian oceans. They usually livecoral reefsand rocky areas of the seafloor, although some are found in tide pools, seagrass, and kelp beds. They are generally nocturnal, emerging at night to hunt crustaceans and sometimes small fish.

As the name suggests, these squids have numerous blue rings on their bodies and arms. These rings are an example of aposematism, where animals use bright colors as a warning to potential predators.

But unlike other aposematic animals like poison dart frogs orvelvety ants, which constantly display their bright colors, blue-ringed octopuses only show their color when they feel threatened.

Krakenhave thousands of chromatophores under their skin. These are specialized cells that allow them to change color instantly. Blue-ringed octopuses display a threat display with these cells and iridophores, a special type of light-reflecting chromatophore that gives blue-ringed octopuses their iridescence.

When alarmed or attacked, these animals quickly change color. They use muscle to make their blue patterns appear and display them on a yellow or cream base with dark pigment cells under the rings, which helps to intensify their color.

Like many other squids, blue-ringed octopuses can use their chromatophores to camouflage themselves. They spend a lot of time hiding in crevices and hiding from animals that might try to eat them.

There may be as many as 10 different species of blue-ringed octopus, although only four have been given scientific names.

The blue-ringed octopus (Hapalochlaena lunulata) is about 12 centimeters long including the arms. This species prefers shallow waters, up to 20 meters deep. It has been found in the waters around Indonesia, the Philippines, Papua New Guinea, Vanuatu and the Solomon Islands.

The southern blue-ringed octopus (Hapalochlaena maculosa) is found up to 50 meters deep along the southern coast of Australia, including around Tasmania. It reaches about 22 centimeters in length and its base can vary from gray-green to whitish, with 50-60 blue rings.

Despite its name, the blue-line octopus (Hapalochlaena fasciata) is also part of the group. It has iridescent blue lines on its mantle (the muscular structure behind the octopus's head that contains all of its organs), but it also has distinctive blue rings on its arms. This species reaches 15 centimeters in length and is found in the waters of eastern Australia, from southern Queensland to southern New South Wales, at depths of up to 20 meters.

The fourth type isHapalochlaena nierstraszi, which has only been officially recorded twice: in 1938 in the waters around the Andaman Islands andEm 2013when one was caught in a trawl near Chennai in southeastern India. Little is known about this species, although the 1938 specimen had a coat length of 16 centimeters (6.3 in).

The blue-ringed octopus: small, alive and deadly (2)

Blue Angel Octopus gift

The vivid threat displays of blue-ringed octopuses aren't just for show.

Symbiotic bacteria in the salivary glands of blue-ringed octopuses produce tetrodotoxin (TTX). This substance is highly neurotoxic and blocks the transmission of nerve impulses. This prevents the muscles from contracting and can be fatal.Some reports say sothat TTX is more than 1,000 times more toxic than cyanide.

TTX is found in a variety of animals including fish, amphibians and shellfish. The pufferfish is a well-known example. These fish can be eaten, but they sequester TTX in their internal organs; therefore, if not properly prepared, they can cause fatal poisoning.

Blue-ringed octopuses distribute TTX throughout their bodies. If eaten by another animal, the TTX acts like a poison. There wasat least one case of human poisoningcaused by someone accidentally eating a blue-ringed octopusfound a studythat swallowing TTX can make it about 50 times less toxic than if administered by other means.

The blue-ringed octopus: small, alive and deadly (3)

Blue-ringed octopuses can also inject TTX and deliver it as venom through an almost painless bite.

Blue-ringed octopus bites are quite rare, but these animals carry a dose of TTX that is lethal to humans. There have been a handful of fatal encounters with these animals.

TTXcan act quickly, rapidly weakening and paralyzing muscles among a multitude of other potentialsSide effectssuch as vomiting and dizziness. Although TTX victims are progressively unable to move, they usually remain conscious and conscious until lack of oxygen renders them unconscious. Death usually occurs from respiratory failure as the diaphragm becomes paralyzed. This can happen in minutes.

There is no antidote for TTX, and most care is supportive, such as B. Ventilation to keep the patient breathing until the toxin is gone.

Are blue-ringed octopuses endangered?

Experts aren't sure how many blue-ringed octopuses there are, and it's unclear whether their populations are dwindling. Although none of the species are officially listed as endangered, human activities can still affect them.

The blue-ringed octopus: small, alive and deadly (4)

One potential impact is on their main habitats. Blue-ringed octopuses are known to inhabit coral reefs.face threatslike warm waters,ocean acidificationand pollution, to name a few. Seagrass is also in decline. Destruction of these habitats threatens the survival of the animals that depend on them.

Blue-ringed octopuses are also traded internationally for keeping in aquariums. Although part of their range is within marine protected areas, these animals are known to be harvested from the wild in areas where there may be very little regulation of collection. They also have a short lifespan, living for 2-3 years andallegedlyIt doesn't do well in transit.

Blue-ringed octopuses would probably not make good pets. Like other squids, they areescape artistthat can get rid of even the safest of tanks. This would make them a hazard to curious children and well-meaning people who might recklessly pick them up and return them to the tank. This naivety is perhaps proved byseveral examplesof people catching wild blue-ringed squid and showing them off on social media, not knowing they are holding one of the most venomous creatures in the ocean.

Blue-ringed octopuses are incredibly beautiful animals, especially when they show off their bright patterns. But despite their diminutive size and pretty colors, it's important to remember that their flashy rings are not an empty threat. If you are lucky enough to see one in the wild, you can safely observe it from a respectful distance, but you should never pick it up.

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Are blue-ringed octopus deadly? ›

Blue-ringed octopuses can inject TTX too, delivering it as a venom via a near-painless bite. Bites from blue-ringed octopuses are reasonably rare, but these animals do carry a dose of TTX that is lethal for humans. There have been a handful of fatal encounters with these animals.

Can you survive a blue-ringed octopus? ›

The paralysis that overcomes the victim is only to their voluntary muscles; they remain fully conscious. Death usually occurs as a result of lack of oxygen. Thus, if mouth to mouth resuscitation is given to a victim of a blue-ringed octopus, they should fully recover.

Can a small octopus hurt you? ›

Octopuses are curious creatures and generally not aggressive toward people. But they will defend themselves if provoked and are capable of causing serious injury — as Bisceglia found out the hard way.

What is the deadly mini octopus? ›

Blue-ringed octopuses produce a potent neurotoxin called tetrodotoxin, a potentially-deadly substance also found in pufferfish. The venom is produced by symbiotic bacteria in the animal's salivary glands and is more toxic than that of any land mammals.

How many people have died from blue ring octopus? ›

Estimates of the number of recorded fatalities caused by blue-ringed octopuses vary, ranging from seven to sixteen deaths; most scholars agree that there have been at least eleven. Tetrodotoxin can be found in nearly every organ and gland of its body.

Can you touch a blue-ringed octopus? ›

But the bright blue coloring says as boldly as it can: don't touch, I'm toxic. Blue-ringed octopuses can kill humans by biting and injecting venom. They bite when they feel threatened, and since we're so much bigger than they are, humans are certainly threatening!

What happens if an octopus bites you? ›

The octopi's salivary glands produce the venom, and the bacteria gets dispersed through their beak. TTX can paralyze a human in minutes. Due to this paralysis, your body wouldn't be able to get enough oxygen, and death from a blue-ringed octopus would occur.

What does an octopus bite feel like? ›

Their bite is usually painless, but the person bitten will feel numb around the mouth, tongue, face and neck and will feel tight in the chest and may have difficulty breathing. Respiratory failure occurs eventually which leads to death if the person is not resuscitated.

Do humans eat blue-ringed octopus? ›

The Department of Marine and Coastal Resources (DMCR) has warned people not to eat grilled blue-ring octopus as its venom is lethal.

Do octopuses get angry? ›

Peter Ulric Tse, a neuroscientist at Dartmouth College who studies octopus cognition, tells the Times via email that octopuses “can express what we would call aggression when they feel threatened or when they feel their territory is under threat.

What to do if bitten by blue-ringed octopus? ›

Blue-ringed octopus
  1. Apply a very firm bandage around the bite and then apply a second bandage over the whole limb. ...
  2. Call 000 for an ambulance or take the patient to a hospital as quickly as possible.
  3. If the person stops breathing, they will need cardio-pulmonary resuscitation (CPR).

Can squids bite you? ›

It was recently discovered that octopuses, cuttlefish and squid are venomous, capable of delivering a toxic bite.

Can you eat baby octopus alive? ›

"It's not recommended. There's a choking hazard predominantly from the suckers getting stuck to the inside the throat, leading to the octopus causing an obstruction." In April 2010, a South Korean woman collapsed and stopped breathing after eating a live octopus, and died in hospital 16 days later.

Is the blue-ringed octopus in America? ›

The deadliest Octopus on the world is called the Blue-Ringed Octopus, and can only be found among the warm and shallow waters of the Australian coast.

What is the most toxic octopus? ›

Blue-Ringed Octopus Venom

The TTX that a blue-ringed octopus injects is so deadly that 1 milligram of it can kill a human. It's one of the most potent toxins on earth, and there is no antidote.

Who would win a blue-ringed octopus or a shark? ›

A shark would win a fight against an octopus. Although we can find cases where an octopus kills a smaller shark, the size disparity is simply too much for an octopus to overcome. Even if the octopus uses camouflage, it can't hide from a shark completely.

How long do blue-ringed octopus live? ›

The blue-ringed octopus is about the size of a pea when hatched then grows to reach the size of a golf ball as an adult. They mature quickly and begin mating the following autumn. Males die after mating. Octopuses, along with squid and cuttlefishes have a short lifespan of about 2 years.

Was the giant octopus real? ›

Share. The giant Pacific octopus is considered the largest octopus species in the world and inhabits the northern Pacific Ocean off the United States up to Alaska and around Japan. The largest individual on record weighed an impressive 600 pounds and measured 30 feet across in length.

Are octopus good pets? ›

Octopuses, in general, are not a great choice for a pet. For one, they are incredibly intelligent and seem to easily get bored. One study [pdf] revealed that octopuses in small tanks outfitted with flowerpots, stones, beads and shells still showed signs of distress and even self-mutilation.

How do you get an octopus off you? ›

Worst-Case Wednesday: How to Escape From a Giant Octopus
  1. Pull away quickly. ...
  2. Do not go limp. ...
  3. Prevent the octopus's arms from wrapping around your arms. ...
  4. Peel the suckers from your body. ...
  5. Detach the octopus from its anchor. ...
  6. Turn somersaults in the water. ...
  7. Swim towards the surface.
Mar 5, 2014

Do octopus like to be petted? ›

"The home-kept species often seem to enjoy a short petting session if they acclimate to humans," she said. "However, I try to note that petting may be more like a cat scratching an itch than any form of affection. On the other hand, they do know individuals and interact differently with different people."

Has a giant squid ever attacked a human? ›

A giant squid allegedly attacked a raft with survivors from the Britannia in 1941, which had been sunk in the South Atlantic. One of the men was dragged away by the squid, and another, Lieutenant Raymond Edmund Grimani Cox, managed to narrowly escape the same fate, though suffering tentacle sucker wounds.

Do octopus turn red when angry? ›

Their coloration also reflects their mood. While their pigmentation is normally brown, octopuses may turn white, which shows fear, or red, which demonstrates anger.

How many hearts does an octopus have? ›

Octopuses have blue blood, three hearts and a doughnut-shaped brain.

Do squid feel hurt? ›

A science-based report from the University of British Columbia to the Canadian Federal Government has been quoted as stating "The cephalopods, including octopus and squid, have a remarkably well developed nervous system and may well be capable of experiencing pain and suffering."

Does octopus feel pain when boiled? ›

Lobsters, crabs, and octopuses can feel pain and should not be cooked alive, says new report. Lobsters, crabs, and octopuses have feelings and should therefore not be cooked alive, a new scientific report has said.

Can an octopus hug you? ›

While diving in the waters of Campbell River in Vancouver, photographer Andrea Humphreys and her friends encountered a giant Pacific octopus who swam up to them and began giving out great big hugs. Humphreys, who is an experienced diver, was thrilled with her extremely close encounter.

Can octopus feel fear? ›

Researchers from York University argue that octopuses, crabs, lobsters, crayfish, and other invertebrates are indeed sentient and can feel pain, anger, fear, and happiness.

Do octopus throw rocks? ›

A study published on Wednesday in the journal PLOS ONE shows that octopuses of at least one species throw silt and shells, sometimes at one another. It's a rare behavior in the animal kingdom, and the study is the first time it has been documented in octopuses.

Do octopuses get sad? ›

They look so "alien," but octopuses feel and remember pain like we do. We can track their emotional reactions. But their deeper feelings are a mystery. Octavia, an octopus at the New England Aquarium in Boston, was old and dying.

How long does blue ring octopus venom last? ›

While their bite may be very toxic, blue-ringed octopuses are generally not a danger to humans; they usually won't bite unless provoked. So what happens if a person does get bitten? The venom lasts between 12 and 48 hours, depending on the size of the person and how much venom they get from the bite.

Why do squid turn red? ›

Male Caribbean reef squid (Sepioteuthis sepioidea ) turn red to attract females and white to repel other males—and can even split the coloration of their bodies down the middle to attract a female on one side and repel a male on the other!

How big is a Kraken? ›

The kraken had very large eyes, and fins protruded from the upper part of its elongated central body. When younger, krakens resembled a pale squid. Their massive tentacles could crush the hull of a galleon. The average kraken was about 100 feet (30 meters) in length and weighed about 4,000 pounds (1,800 kilograms).

Is squid ink poisonous? ›

‌Although squid ink isn't poisonous, it may carry some risks. Eating food made with squid ink can cause an allergic reaction similar to seafood allergy. If you have a shellfish or squid allergy, avoid any foods with squid ink.

Why do squid still move after death? ›

Because this squid was just killed, its muscle cells were still intact and operational. A live squid moves it tentacles by sending an electrical command from its brain to its muscles. The commands say "contract" or "relax." But since this animal lost its head, its brain can't send signals. Salt acts as a substitute.

Can an octopus survive without a heart? ›

The octopus would not be able to survive because that is the heart that provides the whole body with blood, which also helps deliver important oxygen around the body. If you thought three hearts was a lot, you might be even more surprised to learn about the hagfish, which looks kind of like a slimy, sticky eel.

Are purple octopus real? ›

Graneledone verrucosa, the Atlantic cousin of the Pacific warty octopus, is seen off the northeastern U.S. coast in 2013. All Graneledone species have warts, but some are smoother than others. Deep in the Pacific Ocean, pale purple octopuses with giant cartoon eyes roam the seafloor.

How fast can octopus go? ›

Common octopus

But these intelligent invertebrates can scoot along at speeds up to 25 miles per hour. They use a method called jet propulsion, which is also seen in other cephalopods like squid. Octopuses will suck water into a muscular sac, then quickly expel it through a small tube called a siphon.

Are blue-ringed octopus in the beach? ›

The Blue-ringed Octopus can be found on the Northern Beaches in shallow rock pools, hiding in crevices or empty shells of other marine animals. Their venom can be deadly and there is no anti-venom available. If you get bitten, call an ambulance immediately.

What is most poisonous animal? ›

The blue-ringed octopodes (Hapalochlaena spp.) produce tetrodotoxin, which is extremely toxic to even the healthiest adult humans, though the number of actual fatalities they have caused is far lower than the number caused by spiders and snakes, with which human contact is more common.

Can a giant octopus hurt you? ›

The bite of the Giant Pacific Octopus will not only hurt, but it will also inject venom into its target (although this venom is not fatal). What is this? Thankfully, the Giant Pacific Octopus is known to be rather shy and usually friendly towards humans, rarely using its dangerous features to inflict harm.

What's the most venomous creature on earth? ›

Inland taipan (Oxyuranus microlepidotus)

The most venomous snake in the world is considered to be the inland taipan, endemic to central-eastern Australia. It has by far the highest median lethal dose of venom of any snake, and indeed probably any animal, making it the most toxic.

How deadly is a blue octopus? ›

The blue-lined octopus may be small, growing to at most 15 cm, but it can be deadly: its venom can cause breathing failure in humans as well as other animals. Turtles can accidentally consume the octopus when grazing and drown due to the immobilizing toxins.

How painful is a blue-ringed octopus? ›

Signs and symptoms of blue-ringed octopus bite

Their bite is usually painless, but the person bitten will feel numb around the mouth, tongue, face and neck and will feel tight in the chest and may have difficulty breathing. Respiratory failure occurs eventually which leads to death if the person is not resuscitated.


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