Life of Sea |Greater Blue-ringed Octopus(Hapalochlaena lunulata) | Greater Blue-ringed Octopus is also include in the genus of Blue-ringed Octopus. It means that it is one of the most venomous marine in the world. It is similar with Southern Blue-ringed Octopus. Greater Blue-ringed Octopus is found in shallow coral and rock pools, particularly after storms, digging around for crabs. It tends to hide in crevices amongst rocks, inside seashells, and discarded bottles and cans because of its soft-bodied vulnerability. In nature, Greater Blue-ringed Octopus can be found from northern Australia to Japan, including Papua New Guinea, Solomon Islands, Philippines, and Indonesia and as far west as Sri Lanka at depths ranging from 0-20 m.
Species: H. lunulata
Greater Blue-ringed Octopus is slightly smaller than Southern Blue-ringed Octopus. It has body around 5 cm long and arms to 7 cm across the tentacles from tip to tip. The surface of the animal is often covered with numerous papillae (a small projecting body part similar to a nipple in form), giving it a rough texture. Large iridescent blue rings cover the dorsal surfaces of the mantle and web and extend out the arms. Rings on the mantle are up to 8 mm in diameter and number fewer than 25. There is a characteristic short, horizontal iridescent blue line that runs through the eye. When at rest, faint, thin blue rings are usually visible. The name "greater blue-ringed" refers to the size of the rings, not the body size.
Greater Blue-ringed Octopus eats mostly crustaceans such as crabs and shrimp. Also, it eats reef fish that stray too close by. It injects them with a powerful neurotoxin that easily paralyzes them, which allows the octopus to devour its prey. Greater Blue-ringed Octopus spends much of its life in hiding. With the exception of mating rituals, they live alone, concentrating on housing and feeding. Because of its unusual design, Octopodidae has perfected many different modes of locomotion. Greater Blue-ringed Octopus is included in Octopodidae family. Octopodidae can employ the arms for grasping. It is used to crawl along the bottom or, in rare instances, out of the water. However, this creature is not aggressive and will tend to hide or flee if disturbed; it has the reputation of only biting if provoked.
Greater Blue-ringed Octopus blanche its colors while in retreat, and, maybe, flushed with darker brown and purple, flash its characteristic ring markings in electric blue when agitated. While resting, the blue-ringed octopus is a pale brown to yellow color depending on its surroundings. But when alarmed, this octopus displays bright blue rings all over its body and Greater Blue-ringed Octopus carries enough venom to kill 26 adult humans within minutes. Poison fromGreater Blue-ringed Octopus has proven to be fatal to humans especially to young children. There is no anti-venom for this poison.
Although other Octopodidae are used for biomedical research, behavioral research, and as gourmet food source, Greater Blue-ringed Octopus too small and too dangerous for much of these uses. Medical and psychological research are interested in the tetrodotoxin neurotoxin found in its venom for its aphrodisiac effect and its ability to block voltage-sodium channels so action potential in neurons is inhibited or reduced. They also have value as an unusual luxury item. As strange as it may seem, a Greater Blue-ringed Octopus individual was sold for $4000 at an auction in Sidney, Australia recently.