Fun Greater Blue-ringed Octopus Facts For Kids

Moumita Dutta
Jan 16, 2023 By Moumita Dutta
Originally Published on Aug 06, 2021
Edited by Katherine Cook
Amazing greater blue-ringed octopus facts to learn about this species.

One of the deadliest underwater creatures is only 2-4 in (5-10 cm) in length which is difficult to believe, but it is true!

The greater blue-ringed octopus (H. lunulata) is a toxic octopus that can be extremely fatal to human beings.

The name of this species is derived from the unique blue rings which are distributed all over its body, and the most fascinating detail about these bright blue rings is that they are aposematic.

Discovered in the shallow waters of the Indo-West Pacific Ocean particularly in the regions of Australia, these marine animals remain in their burrow and come out only during foraging and mating.

The other species of the blue-ringed octopus comprises southern blue-ringed octopus (Hapalochlaena maculosa) also dubbed as lesser blue-ringed octopus, blue-lined octopus (Hapalochlaena fasciata), and Hapalochlaena nierstraszi.

The specialized structure enables this species to adapt to the various procedure of locomotion, their modified arm assisting them in grasping and crawling at the bottom of the ocean.

Want to know more interesting facts about the greater blue-ringed octopuses then keep reading this article. For more relatable content, check out these giant Pacific octopus facts and blue-ringed octopus facts for kids.

Greater Blue-Ringed Octopus Interesting Facts

What type of animal is a greater blue-ringed octopus?

This marine animal with aposematic rings all over its body is a species of poisonous octopus.

What class of animal does a greater blue-ringed octopus belong to?

These marine animals are filled with venom and considered amongst the deadliest sea creatures belonging to the class of Cephalopoda, order Octopoda, family Octopodidae because of the presence of eight arms, and genus Hapalochlaena.

How many greater blue-ringed octopuses are there in the world?

The octopus is a widespread species especially in Australia but the exact number of greater blue-ringed octopuses has not been estimated. The blue-ringed octopus spends most of its life in its cave but there are unavoidable factors that are a major subject of concern for its ecosystems like bioprospecting, habitat degradation, and human disturbance.

Where does a greater blue-ringed octopus live?

This venomous creature that can kill with its bite is a sea dweller, discovered in the shallow waters of the Indo-West Pacific Ocean and Indian Ocean which includes the areas ranging from the Philippines to Sri Lanka, Papua New Guinea to the coasts of Australia.

The H. lunulata is familiar near the southern coasts of Australia.

Another species of blue-ringed octopus, the Hapalochlaena maculosa, is comparatively smaller than the greater blue-ringed octopus and also inhabits the water of Australia particularly in areas that possess an abundance of seagrasses.

The Hapalochlaena fasciata can be observed near the southern coasts of New South Wales and southern Queensland while Hapalochlaena nierstraszi was once documented in 1938 based on the Bay of Bengal’s specimen.

What is a greater blue-ringed octopus' habitat?

According to its geographical distribution which comprises the areas of the Indian and Pacific Oceans, the habitat of these octopuses is shallow subtropical which has a mixed seabed containing rubbles, sandy regions, and reefs.

Greater blue-ringed octopuses remain in their cave for a long period.

It only emerges out of the cave when it searches for prey and desires a mate because the absence of any exoskeleton makes them vulnerable. However, it is not hard to identify where it resides as the front of the opening of its cave is always littered with shells or other remaining parts of prey.

As these octopuses cannot survive in open water, they dwell at the bottom and it is their modified arm that facilitates their locomotion.

Who do greater blue-ringed octopuses live with?

Although there is not much data, greater blue-ringed octopuses like other species of blue-ringed octopus do not go outside of their cave, so it must be assumed that they are solitary animals. Greater blue-ringed octopuses are also extremely territorial, so it may attack its opponent exactly like it strikes its prey if it feels threatened.

How long does a greater blue-ringed octopus live?

The lifespan of a greater blue-ringed octopus is approximately two to three years.

How do they reproduce?

The identification of sex and mating behavior is exceptionally unusual amongst the H. lunulata.

There is no definite mating season as it varies according to its geographical distribution. Nonetheless, as the physical contact is entirely unrestricted from size and gender, there are no behavioral modifications based on the gender of this species.

The female is first approached by the male and extends its arms to caress the female, followed by the male climbing on the back of the female, inserting the tip of hectocotylus under the mantle of the female.

Spermatophores are released by the males into the female's oviduct and this process can last for an hour. The males are unable to figure out the gender of their partner until coitus begins.

The male octopus perishes after successfully copulating with the female and the female lays 50-100 eggs which she keeps protected underneath her arms during the incubation period and eventually dies as she does not eat while she protects her eggs.

What is their conservation status?

The conservation status of the greater blue-ringed octopus is Least Concern by the International Union of Conservation of Nature. However, factors like overfishing and habitat degradation can affect the population of these octopuses. This octopus plays a vital role in expanding the marine food web balance and stabilizing biodiversity.

Greater Blue-Ringed Octopus Fun Facts

What do greater blue-ringed octopuses look like?

The length of this octopus is less than 4 in (10 cm) and weighs 0.2 lb (80 g). The arms are modified to enable grasping and locomotion underneath the ocean.

The skeleton is nonexistent like with all other species of the Octopodidae, meaning they have a soft body. Just like the southern blue-ringed octopus, the greater blue-ringed octopus has a bright blue rings that covers its body and the color of the skin may range from yellow ocher and light brown.

Greater Blue-Ringed Octopus

How cute are they?

Many people may not find them cute because of their slimy appearance, just like a coconut octopus.

How do they communicate?

They use their arms to communicate with their mates and flash their iridescent blue rings as a warning.

How big is a greater blue-ringed octopus?

The greater blue-ringed octopus size is around 2-4 in (5-10 cm). They are smaller than a mimic octopus.

How fast can greater blue-ringed octopuses move?

A common octopus can swim 25 mph (40.2 kph) but the accurate speed of a greater blue-ringed octopus is not known.

How much does a greater blue-ringed octopus weigh?

The weight of this octopus is approximately 0.2 lb (80 g).

What are the male and female names of the species?

There are no different names for males and females of this marine creature.

What would you call a baby greater blue-ringed octopus?

Once the eggs hatch, the babies are known as larvae and it is a size of a pea and once grown it becomes the size of a golf ball.

What do they eat?

The greater blue-ringed octopus is a carnivore and it preys on crabs, mollusks, and fishes. The octopus grabs the prey with its arms and after biting, it releases the venom which ultimately paralyzes the prey and kills it.

Are they dangerous?

This octopus species is extremely dangerous because of the venom present in its glands and organs, but it will not attack immediately. Once sensing a threat, the greater blue-ringed octopus flashes its iridescent blue ring as an alarm, however, if the threat persists it will release tetrodotoxin that can kill humans.

Would they make a good pet?

No, because they are extremely poisonous and could kill humans. Keeping them as a pet is not a good idea.

Did you know...

In Michael Crichton’s book ‘State Of Fear’ the venom of the blue-ringed octopus was made into a weapon by the terrorist organization.

They can regenerate a lost or injured arm within six weeks.

While predators like whales and eels prey on them, there are times when they become prey if the octopus bites them.

Is the greater blue-ringed octopus's bite dangerous?

The venom produced by this octopus in its salivary glands contains tetrodotoxin, which is a highly toxic substance that can immediately cause respiratory arrest, blindness, paralysis, nausea, and heart failure. The bite of a greater blue-ringed octopus is proved to be fatal to human beings.

The bite may not be initially painful but it takes around 15-20 mins for the venom to initiate the effects. The preliminary stage is paraesthesia when the victim starts feeling numbness in various regions.

The next stage that follows is hypotension and paralysis of muscles. Death can happen anywhere between 20 minutes to 24 hours once the symptoms start developing.

Tetrodotoxin is universally present in all its organs and glands and the mother passes down the tetrodotoxin to the offspring by inoculating the neurotoxin into the eggs before hatching.

There is no particular antidote for the venom but treatment like keeping the victim in a ventilator where artificial respiration can be provided till the effect of venom wears off can save the life of the victim. Although, their bite can kill, there are cases when the victim has survived.

If a victim can withstand the initial 24 hours after being bitten, then the victim can recover completely.

What sounds do greater blue-ringed octopuses make?

Greater blue-ringed octopuses attempt to communicate by using their flashing behavior. These octopuses flash their iridescent blue rings for three seconds as a warning but the sounds made by these creatures are not specified.

Here at Kidadl, we have carefully created lots of interesting family-friendly animal facts for everyone to discover! Learn more about some other cephalopods from our colossal squid interesting facts and vampire squid fun facts pages.

You can even occupy yourself at home by coloring in one of our free printable greater blue ringed octopus coloring pages.

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Written by Moumita Dutta

Bachelor of Arts specializing in Journalism and Mass Communication, Postgraduate Diploma in Sports Management

Moumita Dutta picture

Moumita DuttaBachelor of Arts specializing in Journalism and Mass Communication, Postgraduate Diploma in Sports Management

A content writer and editor with a passion for sports, Moumita has honed her skills in producing compelling match reports and stories about sporting heroes. She holds a degree in Journalism and Mass Communication from the Indian Institute of Social Welfare and Business Management, Calcutta University, alongside a postgraduate diploma in Sports Management.

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