Hapalochlaena fasciata
Hapalochlaena lunulata
Hapalochlaena maculosa
Hapalochlaena nierstraszi The Blue-ringed Octopus (genus Hapalochlaena) are small octopuses that live in tide pools in the Pacific, in places from Japan to Australia.

Overview

There are four species of Hapalochlaena:

• Greater Blue-ringed Octopus (Hapalochlaena lunulata)
• Lesser Blue-ringed Octopus or Southern Blue-ringed Octopus (Hapalochlaena maculosa)
• Blue-lined Octopus (Hapalochlaena fasciata)
• Hapalochlaena nierstraszi

An individual Blue-ring Octopus tends to blend into its environment until provoked, when it turns quickly into a bright yellow creature with blue rings or lines. It camouflages itself by using special dermal cells called chromatophores. It hunts small crabs, but will bite an attacker, even a human if provoked or stepped on.

Its saliva, which can be instilled through a painless bite or can be spit, contains the bacterial poison tetrodotoxin, to which there is no known antidote. Tetrodotoxin, the same poison found in Pufferfish and Cone Snails, can cause paralysis leading to respiratory arrest, which can then lead on to cardiac arrest because of lack of oxygen. First aid treatment is pressure on the wound and CPR, and hospital treatment involves respiratory assistance until the toxin is washed out of the body. The symptoms can vary in severity, with children being the most at risk because of their small body size. If the victims live through the first 24 hours after the bite they generally go on to make a complete recovery.

Feeding

Their diet typically consists of small crab, and shrimp, but may also feed on fish if they can catch them. They pounce on their prey, bite them then use their beaks to tear off bits. They then suck out the flesh from the crustacean's exoskeleton. In lab conditions they have been seen to eat each other although they have not been studied in the wild.

Mating

Males mate with the females by grabbing her mantle, then transferring sperm packets by inserting his hectocotylus into her mantle cavity over and over again. Mating continues until the female has had enough, and in at least one species has to remove the over-enthusiastic male by force.

Blue ringed octopus females lay only one clutch of about fifty eggs in their lifetime towards the end of autumn. Eggs are laid then incubated underneath the females arms for approximately six months, and during this process she will not eat. After the eggs hatch the female dies, and the new offspring will reach maturity and be able to mate by the next year.

Blue-ringed octopus in pop culture

• The blue-ringed octopus starred in the James Bond movie of Octopussy as a tattoo, sign of "an old secret order of female bandits and smugglers"
• A blue-ringed octopus was used as a weapon in an episode of the television show Profiler. The species name was mentioned but was a fusion of the Greater and Lesser species names: Hapalochlaena maculata.
• This octopus was also used as a weapon in the Michael Crichton novel State of Fear.

External links

• What makes blue rings so deadly
• Hapalochlaena The Blue-Ringed Octopus
• CephBase: Hapalochlaena