Blue-ringed octopus

Blue-ringed octopus
Greater blue-ringed octopus (Hapalochlaena lunulata)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Order:	Octopoda
Family:	Octopodidae
Genus:	Hapalochlaena Robson, 1929[1]
Type species
Hapalochlaena lunulata Quoy & Gaimard, 1832
Species
H. fasciata (Hoyle, 1886) H. lunulata (Quoy & Gaimard, 1832) H. maculosa Hoyle, 1883 H. nierstraszi (?) Adam, 1938

Blue-ringed octopuses, comprising the genus Hapalochlaena, are four extremely venomous species of octopus that are found in tide pools and coral reefs in the Pacific and Indian Oceans, from Japan to Australia.^[2] They can be identified by their yellowish skin and characteristic blue and black rings that can change color dramatically when the animals are threatened. They eat small crustaceans, including crabs, hermit crabs, shrimp, and other small sea animals.

They are some of the world's most venomous marine animals.^[3] Despite their small size—12 to 20 cm (5 to 8 in)—and relatively docile nature, they are very dangerous if provoked when handled because their venom contains a powerful neurotoxin called tetrodotoxin.

The species tends to have a lifespan around two to three years, which may vary depending on factors such as nutrition, temperature, and the intensity of light within its environment.