Dead Ringers

By Chris Doyle on November 15, 2012 in Other

Australia is renowned for being home to some of the most venomous animals on the planet, and even the beaches of Sydney’s Eastern Suburbs, as idyllic as they may seem, are no exception. In fact, this beautiful part of the world is home to one of the deadliest creatures of them all – the blue-ringed octopus.

Despite only reaching a size no bigger than a golf ball, the blue-ringed octopus is said to contain enough venom to kill twenty-six adult humans within minutes. The venom is produced by bacteria that live in the salivary glands and is transferred in the octopus’s saliva. It is a powerful neurotoxin that is ten thousand times more toxic than cyanide and paralyses the breathing muscles. Bites from the blue-ringed octopus are painless and victims do not usually even notice they have been bitten until they have difficulty breathing. With no known antidote, the only treatment is heart massage and artificial respiration until the toxin is eventually excreted by the body, which can take up to several painfully long hours.

The way that the blue-ringed octopus can kill its prey without even biting it is a testament to the power of its venom. Usually hunting crabs and shrimp, the blue ringed octopus can sidle up alongside its intended meal and release the venom into the water. The prey quickly becomes paralysed and the octopus then uses its jaw-like beak to break through the tough shell and suck out the flesh. Blue-ringed octopuses can also catch small fish by ambushing them and biting them while they are wrapped up in their arms.

Before you go banning your loved ones from the beach this summer, take comfort in knowing that bites to humans are extremely rare. While blue-ringed octopuses are common in Sydney, they are hardly ever seen as they prefer to hunt at night and spend most of the day hiding out under rocks and inside shells. They are also extremely timid and, even when spotted, will only bite if provoked or forced to defend themselves. Most bites have occurred when the octopuses have been handled and, according to the Australian Venom Research Unit, only two fatalities have ever been recorded. Still, it is important to be aware of their presence, particularly for parents with young children who often enjoy exploring the rock pools that the octopuses prefer to hide out in.

There are actually three species of blue-ringed octopus found in Australia, with the most common species in Sydney being the blue-lined octopus (Hapalochlaena fasciata). All species have a dull yellowish-brown colour, with the distinguishable blue rings or clumps only appearing when the octopus is agitated. The blue markings serve as a warning that the octopus is ready to bite, or worse, that it has already bitten!

So if you ever see a small octopus, assume it to be a blue ringer whether it has blue colouring or not and leave it as you found it, or else you may end up turning blue yourself.