There are several species of Hapalochlaena, four of which have been confirmed. The greater blue-ringed octopus, southern blue-ringed octopus, blue-lined octopus, and Hapalochlaena nierstraszi. Despite their reputation as deadly animals, these creatures are not aggressive. They remain in small crevasses and will only use their venom if provoked. It’s not unusual to find them hiding in ocean trash as well. 

Their venom is produced from two salivary glands and is far more toxic than any land animal. When an animal comes into contact with the venom they become paralyzed, something that is incredibly dangerous in the ocean. The victim remains conscious throughout their paralysis. It’s important to provide treatment right away, which usually includes placing the patient on a ventilator. Records indicate that atlas three people have died from coming into contact with their venom. 


Appearance 

The blue-ringed octopus is identifiable through its yellowish skin and blue and black rings that cover its body. These change colors when the animal believes it is threatened. These creatures have a soft body and eight arms that are covered in suckers. There are up to twenty-five rings around their body, around .3 inches in diameter each. The center of each ring is dark brown with blue and black circles around it. The faint blue becomes brighter when the octopus feels it is in danger. 

They are as small as a grapeseed when they are born, according to the Aquarium of the Pacific. The females are slightly smaller than the males, but they grow up to around 1.97 inches in length with arms that extend out to around 2.8 inches. They only weigh around 10-100 grams on average. They live to be about one year old.

Ring pattern on blue-ringed octopuses
Ring pattern on blue-ringed octopuses

Credit: Roy Caldwell


Diet

This unique creature feeds on small crabs, including hermit crabs and small fish. They are ambush predators. This means that rather than waiting for their prey to come to them, they punch on it and use their arms beak to hold it down. Their saliva paralyzes their prey; through a hold, they stab into its body with their beak, allowing it to be consumed. The octopus then sucks out the flesh from the crab or fish, leaving the hard parts behind, according to the Aquarium of the Pacific.

Reproduction 

The blue-ringed octopus can reproduce from a young age, around one year old or less. The male finds a female and attempts to insert his hectocotylus into her mantle cavity. The female may lay up to 100 eggs after mating is over. These eggs, like the octopuses themselves, contain venom. When the eggs hatch, the paralarvae is quite small, only 4 millimeters long. They swim freely before settling on the ocean floor. Interestingly, the female dies shortly after the eggs hatch, according to the Aquarium of the Pacific. 

Blue-ringed octopus in New South Wales, Australia
Blue-ringed octopus in New South Wales, Australia

Credit: David Breneman


Facts about the Blue-ringed Octopus

  • The IUCN does not list the blue-ringed octopus on their lists of endangered or threatened species and at this moment they are not protected. 
  • The blue-ringed octopus can reproduce from a young age. 
  • They only live for around a year, scientists think.
  • They are as small as a grapeseed when they are born.
  • Their venom is produced from two salivary glands and is far more toxic than any land animal.
  • The blue-ringed octopus is identifiable through its yellowish skin and blue and black rings that cover its body.


FAQs 

Is the blue-ringed octopus native to Australia?

Yes, a certain species of this octopus, the  Hapalochlaena maculosa, can only be found in the waters around Australia. They live at relatively shallow depths, from 0-50 meters below the surface. 

What happens when you touch a blue-ringed octopus?

Within a matter of seconds, you will become paralyzed. You won’t be able to move your body, but you will remain conscious. This is incredibly dangerous in the open ocean. 

Can you own a blue-ringed octopus?

Technically yes. But, it is not advisable. Despite their relatively cheap price tag, these animals are not to be taken lightly. Coming into contact with their venom could result in serious injury for the owner or for anyone else in the vicinity. 

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

It’s unknown how many blue-ringed octopuses live in the Earth’s oceans at the moment. But, scientists believe that there are at least three, and as many as ten, species living throughout the world. 

Can you eat a blue-ringed octopus?

Yes, there are some people around the world who eat the blue-ringed octopus. Its venom is neutralized through the cooking process as long as the temperature is high enough. But, scientists warn against it. 

Has anyone survived a blue-ringed octopus bite?

Yes, it is possible to survive a blue-ringed octopus bite. If the patient is retrieved from the water quickly and taken to a medical facility, they are likely to live. Studies show that patients who live past the first twenty-four hours are likely to survive.