Small but Deadly - The Blue Ringed Octopus

Put the words ‘danger’ and ‘ocean’ together and most people will think of sharks. But what if you were asked to look at something much smaller and much closer to home- the blue-ringed octopus. At only 10cms long when fully grown, the blue-ringed octopus may not seem like a major threat. However, these tiny marine creatures are some of the ocean’s most distinctive and venomous inhabitants and can be found along beaches from the Sea of Japan to the south coast of Australia. Despite their deadly bite, blue-ringed octopuses aren’t aggressive. Their distinctive blue rings are only shown when they feel threatened and function as a warning to predators. Fortunately, despite their formidable reputation, and being very common in coastal waters, blue-ringed octopuses are rarely encountered. The venom in their bite serves to paralyse all the muscles in their victim, and so kill them, but there is one muscle that is not affected- your heart. The heart will keep pumping after a bite from a blue-ringed octopus and people have actually been kept alive by mouth-to-mouth resuscitation. So, should you be with someone who is bitten by a blue ringed octopus just apply the same first aid as with snake bite- keep the victim still, firmly bandage the wound, call for help and be ready to apply CPR. Of course, prevention is better than cure so be very careful when exploring rock pools and reefs. Remember, it is their home, not yours. 

Northern blue-ringed octopus (Hapalochlaena lunulata)
Credit: Clay Bryce, WA Museum