The blue-ringed octopus, shown in this photograph, is both beautiful and dangerous. The octopus has a venomous bite that has killed several people.
© Richard Merritt, FRPS/Getty Images

Australia is famous for its unique culture, metropolitan cities, and unusual wildlife, among other things. Each week, this seasonal feature will spotlight one of Australia’s many wonders.

What has eight arms and a venomous bite? The blue-ringed octopus. The blue-ringed octopus is a kind of sea animal found in the tropical and subtropical waters of Sri Lanka, the Philippines, Australia, and south Japan. It is recognizable by its psychedelic spots that are ringed with bright blue. The bodies of most blue-ringed octopuses measure about 11/2 to 21/2 inches (4 to 6 centimeters) in diameter. They measure up to about 4 inches (10 centimeters) with their tentacles.

Blue-ringed octopuses like to hide under rocks or in crevices during the day, coming out during the night. Though they inhabit depths as far down as 160 feet (50 meters), you don’t want to get caught near their parrotlike beaks. Sometimes, they bite people. The venom from their salivary glands then enters the wound. Several people have died from bites by these animals. The bite is often painless. A small spot of blood on the skin when the animal is removed may be the only clue that a bite has been sustained. The first effect of the venom is a rapidly developing numbness. Victims often stop breathing, requiring mouth-to-mouth resuscitation. Treatment is the same as for snakebite. No specific antidote is available.

The blue-ringed octopuses belong to the genus Hapalochlaena.