Australia is home to many things, including the Opera, the Australia Zoo, and a tiny octopus so deadly that a single bite can kill a person.

Although its body is the size of a golf ball, the blue-ringed octopus packs quite a punch. Image via Museum Victoria.
Although its body is the size of a golf ball, the blue-ringed octopus packs quite a punch. Image via Museum Victoria.

The blue-ringed octopus is cute enough for people to spot and want to play with. This can be a fatal mistake, and death can come within a day of being bitten. If the octopus bite contains venom (which is not always the case):

The onset of symptoms can be quite rapid. Within five to ten minutes, the victim begins to experience parasthesias and numbness, progressive muscular weakness and difficulty breathing and swallowing. Nausea and vomiting, visual disturbances and difficulty speaking may also occur. In severe cases, this is followed by flaccid paralysis and respiratory failure, leading to unconsciousness and death due to cerebral anoxia. Interestingly, the victim’s heart continues to beat until extreme asphyxia sets in. Some victims report being conscious, but unable to speak or move. They may even appear clinically dead with pupils fixed and dilated.

The venom is contained in the saliva of these octopi, and has been found to be the same tetrodotoxin found in pufferfishes, snails, and other species. Tetrodotoxin is “one of the most potent toxins known to mammals.” It turns out that such a diverse array of species all have this toxin because they are home to specific bacteria that produce tetrodotoxin. Scientists conducted experiments with rabbits to determine just how deadly this venom is, and found that a single, tiny octopus has enough venom in its saliva to fatally paralyze twenty six people! These octopi are so deadly that scientists who study them are required to work in pairs, and must be trained in CPR in order to be able to resuscitate their partners if bitten. There is no known antidote for tetrodotoxin, and the fact that many people who are bitten by these octopi don’t notice it until it is almost too late makes these animals even deadlier.  

So what is it like to be bit by one of these animals? To begin with, you’ll see a small, pencil-sized octopus change its vibrant colors (as a way to warn you to stay away!). As you get closer, you probably won’t even feel that you have been bit, and then:

Your lips are going numb. So is your face. You want to yell for help but can’t: It’s getting harder to speak. And your stomach feels—oh, gross! Right in front of everyone. Somebody calls an ambulance. It’s getting tough to stand. It’s getting tough to breathe. The numbness is spreading to your hands, feet, and chest. And you continue to be aware for every agonizing moment of it. You get to the hospital in time. You get hooked up to a ventilator, the machine forcing air into your lungs because your diaphragm is paralyzed. No antidote, the doctors say. You have to wait it out. About 15 long hours later, your muscles start working again. They take you off the ventilator. You can breathe.

Why do these octopi have such deadly toxins? To begin with, they have a symbiotic relationship with the toxin-producing bacteria. They give the bacteria homes, and the bacteria allow them to kill predators and prey with ease. They mostly eat crabs and shrimp, so their venom is perfect for paralyzing them after they spear them with their sharp beak. It just so happens that what helps them kill their prey can also be deadly for humans.

All of this helps to explain their place in popular culture. In the 007 movie Octopussy, the Octopus Cult that James Bond fights against is symbolized by the blue-ringed octopus. I haven’t seen this movie, but I’d bet that they are quite deadly, although I’d bet that Bond ultimately triumphs over their toxic evil.

James Bond vs Blue-Ringed Octopus. Image via Wikipedia.
James Bond vs Blue-Ringed Octopus. Image via Wikipedia.

So, the next time you’re swimming in the waters of Australia, keep your eyes peeled for this tiny little octopus. Its cuteness can be deceiving.

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