A woman didn't expect to get injured while swimming in Sydney, Australia. She picked up a shell unsuspectingly when a small blue-ringed octopus fell from it and bit her.

Swimming Got Bitten by a Blue-Ringed Octopus

The 30-year-old swimmer was enjoying the waters at Sydney's Chinamans Beach in Mosman Thursday. At around 2:45 p.m., she picked up a shell in the water without knowing that a small blue-ringed octopus was inside. The cephalopods, usually between 4 cm to 6 cm, fell out and bit her twice on the stomach, according to NSW Ambulance Inspector Christian Holmes in a statement obtained by Yahoo! News.

The woman is still in the hospital and is being monitored closely. She was reportedly experiencing abdominal pain around the bite area, so paramedics applied pressure and a cold compress before they took her to Royal North Shore hospital to be monitored and treated for further symptoms, Inspector Holmes added.

A blue-ringed octopus bite is reportedly a rare call for them. However, they are extremely venomous.

The outlet noted that the blue-ringed octopus' venom, called tetrodotoxin, is 1,000 times more powerful than cyanide in humans.

The bites are rare and seldom break the skin. They are also often undetected but have disastrous effects, so they should be avoided if possible.

The incident came just weeks after another blue-ringed octopus was spotted just meters away from children playing in the water. The sea creature was found within the netted area of Gunnamatta Bay near Cronulla, and a man managed to scoop it using a child's sand bucket and released it safely and away from the swimmers.

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What Is a Blue-Ringed Octopus?

Blue-ringed octopuses are stunning but alarming at the same time. They earned their name due to the eponymous iridescent blue rings covering their body and arms. They belonged to a group of highly venomous cephalopods, according to the Natural History of Museum.

They are small and have been found in the Pacific and Indian oceans. They usually live in coral reefs and rocky areas of the seafloor.

Blue-ringed octopuses are nocturnal. They emerge at night to hunt crustaceans and small fish.

The rings are examples of aposematism, where animals use bright colors to warn would-be predators. However, unlike other aposematic animals like poison dart frogs or velvet ants, which permanently display their bright colors, blue-ringed octopuses only show off their blue colors when they feel threatened.

Normally, they do not bite unless threatened or taken out of their environment. When they don't feel threatened, they usually look like regular brown octopuses, Nine.com.au reported.

Blue-ringed octopuses' salivary glands have symbiotic bacteria that produce tetrodotoxin (TTX), a potent neurotoxic substance. It blocks the transmission of nerve impulses and stops muscles from contracting, which may lead to potentially deadly consequences.

When they are eaten, the TTX acts as a poison. There is at least one case of human poisoning after one mistakenly eats a blue-ringed octopus. However, according to a study, swallowing TTX is 50 times less toxic than when delivered through other means.

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