page_title: Blue-ringed octopus
section_title: Venom
hierarchical_section_title: Blue-ringed octopus / Toxicity / Venom
caption_attribution_description: Photo of a blue-ringed octopus taken by David Breneman underneath the coal loading jetty at Catherine Hill Bay in NSW, Australia on the 24th of March, 2007.
context_page_description: Blue-ringed octopuses, comprising the genus Hapalochlaena, are four highly venomous species of octopus that are found in tide pools and coral reefs in the Pacific and Indian oceans, from Japan to Australia. They can be identified by their yellowish skin and characteristic blue and black rings that change color dramatically when the animal is threatened. They eat small crustaceans, including crabs, hermit crabs, shrimp, and other small animals.
  They are recognized as one of the world's most venomous marine animals. Despite their small size—12 to 20 cm —and relatively docile nature, they are dangerous to humans if provoked when handled because their venom contains the powerful neurotoxin tetrodotoxin.
  The species tend to have a lifespan of approximately two years. This can vary depending on factors such as nutrition, temperature and the intensity of light in its habitat.
context_section_description: The octopus produces venom containing tetrodotoxin, histamine, tryptamine, octopamine, taurine, acetylcholine and dopamine. The venom can result in nausea, respiratory arrest, heart failure, severe and sometimes total paralysis, blindness, and can lead to death within minutes if not treated. Death is usually from suffocation due to paralysis of the diaphragm.
  The major neurotoxin component of the blue-ringed octopus is a compound that was originally known as maculotoxin but was later found to be identical to tetrodotoxin, a neurotoxin also found in pufferfish, and in some poison dart frogs. Tetrodotoxin blocks sodium channels, causing motor paralysis, and respiratory arrest within minutes of exposure. The octopus's own sodium channels are adapted to be resistant to tetrodotoxin. The tetrodotoxin is produced by bacteria in the salivary glands of the octopus.
  Direct contact is necessary to be envenomated. Faced with danger, the octopus's first instinct is to flee. If the threat persists, the octopus will go into a defensive stance, and display its blue rings. If the octopus is cornered and touched, the person would be in danger of being bitten and envenomated.
  Tetrodotoxin can be found in nearly every organ and gland of its body. Even in sensitive areas such as the Needham's sac, branchial heart, nephridia, and gills, tetrodotoxin tested positive and has no effect on the creature’s normal functions. This may be possible through a unique blood transport. The mother will inject the neurotoxin into her eggs to make them generate their own venom before hatching.
caption: Blue-ringed octopus from New South Wales, Australia
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