A male interested in mating approaches a female just close enough to stretch out a modified arm, the hectocotylus, and caress the female. This arm has a deep groove between the two rows of suckers and ends in a spoon-like tip. After a period of caressing the female with the tip of the hectocotylus, the male inserts its arm under the mantle of the female, and the spermatophores then travel down the groove on the hectocotylus to the female's oviduct. Soon after mating, the female begins to lay 60-100 eggs, which she carries in a cluster underneath her tentacles. She then guards them for the next 50 days. The eggs hatch into planktonic paralarvae and spend their first weeks as ocean plankton, drifting at the surface. After gaining weight, they drop to the bottom. Because she stops eating while brooding her eggs, the mother dies almost as soon as they hatch. The young are ready to reproduce around four months after hatching.
(Ellis 1991, Encarta 1998, Environment Australia 1999, Stewart 1997, Roper and Hochberg 1988)
Poison from Hapalochochlaena sp. has proven to be fatal to humans especially to young children. There is no antivenom for this poison. Of the several human fatalities attributed to this animal, all have involved the animal being picked up. The bite itself may not even be felt. Five minutes or so later however, the victim may complain of dizziness and increasing difficulty in breathing. The powerful venom acts on the victim's voluntary muscles, paralyzing the muscles required for body movement and breathing. Artificial respiration is necessary to maintain life. The poison gradually wears off after 24 hrs, apparently leaving no side effects. (Campbell 2000, Environment Australia 1999, Norman 2000)
Although other Octopodidae are used for biomedical research, behavioral research, and as gourmet food source, Hapalochochlaena sp. are 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 H. lunulata individual was sold for $4000 at an auction in Sidney, Australia recently.
(Brenner and Elgar 1999, Ellis 1991, Melki 2000)
H. lunulata is carnivorous, feeding primarily on fish, crabs, mollusks and other small marine animals. It hunts every thing that it is able to overpower. It ambushes prey from the background. H. lunulata often lures its victim by wiggling the tip of an arm like a worm; or it glides near and pounces on a crab, trapping the prey in its arms and dragging it towards its powerful beak-like jaws. Once it has bitten its prey, the octopus injects it with poisonous saliva to kill it. Either H. lunulata cracks prey open with its jaws or it disarticulates them, and with the tips of its arms, removes any vestige of the edible parts. H. lunulata does not employ its beak other than to take from the suckers the portions that it has removed.
(Hutchinson 1998, Ellis 1991, Encarta 1998, Environment Australia 1999)
Hapalochochlaena sp. are found in the IndoWest Pacific and Indian Oceans. They are very common in shallow waters around the coast of Australia particularly in the cooler areas along the southern coast. Hapalochochlaena lunulata specifically is found along the coasts of Northern Australia and farther north in the tropic western Pacific Ocean.
(Ellis 1991, Environment Australia 1999, Norman 1998, Roper and Hochberg 1988)
Biogeographic Regions: indian ocean (Native ); pacific ocean (Native )
-H. lunulata- 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. It is easy to identify the home of -H. lunulata - or any Octopodidae: The area immediately in front of the opening is littered with the shells and hollowed-out legs of various crustaceans. It occupies a particular nest for a long time and ventures forth only to hunt for food or look for a mate. However, it cannot resist a new nest when one is offered. They, as well as other Octopodidae, are bottom dwellers and are not found in open water. Although Octopodidae may venture onto dry land in pursuit of a crab, if it remains there Octopodidae is doomed: Within half an hour, it will die from suffocation.
(Campbell 2000, Ellis 1991, Encarta 1998, Environment Australia 1999, Stewart 1997)
Aquatic Biomes: reef ; coastal
A soft body that rapidly changes color and texture characterizes the family Octopodidae. An octopus has no skeleton and therefore is astonishingly compressible; Octopodidae can ooze through an opening no bigger than one of its eyeballs. Its incredible flexibility comes from its musculature, which consists of fibers that run in three directions, permitting it to change shape. Like all Mollusca, Octopodidae possesses a mantle. However, the mantle is fused with the cephalized head on the dorsal side. The "skin" of Octopodidae is equipped with chromatophores, which are pigment cells that an animal can expand or contract by muscular action. These cells vary in color, and as the animals expands some or contracts others, its color changes. The nervous system consisting of a well-developed brain, controls the color changes an Octopodidae makes in response to its moods and surroundings. The central nervous system of the octopus is the largest and most complex in the invertebrate world, rivaling that of many vertebrates, including mammals. Also analogous with the vertebrates, members of Octopodidae possess two large, complex eyes that are camera-like in structure, and their vision is acute. Although Octopodidae has a closed circulatory system like higher animals as well, the blood is a poor carrier of oxygen. As a result, Octopodidae tires easily. To stay alive, it relies on a system involving three hearts and permanently high blood pressure. A major distinguishing feature of Octopodidae is its eight muscular arms, which radiate out from the body around the beak-like jaws. In males, the third right arm is modified into a hectocotylus for mating. Each arm bears two rows of whitish suckers that can move independently. Each sucker may have 10,000 neurons to handle both taste and touch, and an octopus has thousands of suckers. Octopodidae has an ability to regenerate an injured or lost arm. It usually takes about 6 weeks for an arm to regenerate. It has been found that, along with arms, Octopodidae can even regenerate part of an eye that is damaged.
The blue-ringed octopi actually include four closely related species Hapalochochlaena marculsa, Hapalochochlaena lunulata, Hapalochochlaena fasciata, and Hapalochochlaena nierstraszi . Its larger rings distinguish Hapalochochlaena lunulata, the Greater blue-ringed octopus, from the other species. Hapalochochlaena lunulata is about 20 cm at maximum spread, but under normal circumstances, it appears much smaller than this. H. lunulata is dark brown to dark yellow in color, but with brilliant blue rings thought to be warning coloration that "glow" when it is angry. The reason the rings are blue is thought to be that the visual range of the octopus is most sensitive in the blue part of the spectrum. At the small beak at the junction of its eight arms rather than manufacturing ink, H. lunulata makes poison like the tetrodotoxin found in poisonous puffer fishes. Bacteria in their salivary glands produce it. The venom, contained in its saliva and designed to subdue or kill its prey is particularly lethal to human beings.
(Campbell 2000, Ellis 1991, Encarta 1998, Environment Australia 1999, Norman 1998, Roper and Hochberg 1988, Stewart 1997)
Range mass: 10 to 100 g.
Other Physical Features: ectothermic ; bilateral symmetry
The greater blue-ringed octopus is, despite its vernacular name, a small octopus whose size does not exceed 10 centimeters, arms included, for an average weight of 80 grams. Its common name comes from the relatively large size of its blue rings (7 to 8 millimeters in diameter), which are larger than those of other members of the genus and help to distinguish this type of octopus. The head is slightly flattened dorsoventrally and finished in a tip. Its eight arms are short.
The coloration of this octopus varies with the circumstances and the ambient environment, from yellow ocher to light brown through whitish (when inactive). The blue rings, which number around 60, are spread throughout the entire animal's coat. The rings are roughly circular and are based on a darker blotch than the background color of the coat. A black line, with thickness varying to increase contrast and visibility, borders the electric blue circles. The blue rings are an aposematic adornment to clearly show to all potential predators that the octopus is highly venomous. The octopus also has characteristic blue lines running through its eyes.
The greater blue-ringed octopus is widespread throughout the tropical and subtropical waters of the Indo-West Pacific, from Sri Lanka to the Philippines and from Australia to Papua New Guinea, the Solomon Islands and Vanuatu.:174 The animal likes shallow waters with mixed seabed (such as rubble, reefs and sandy areas). As is true for all octopuses, it lives in a burrow and only comes out to search for food or a mate. The entrance of the shelter is littered with remains from meals (empty shells and crab shell and legs) and is easily identifiable.
The greater blue-ringed octopus is a benthic animal that has a solitary way of life. The breeding season varies according to geographical area. The female lays 60 to 100 eggs, which are kept under the female's arms during the incubation period, which lasts about a month. Newborns have a brief planktonic development passage before settling on the seabed.
The greater blue-ringed octopus is capable of inflicting a deadly bite to its predators that can even be fatal to humans. Octopuses from genus Hapalochlaena have two kinds of venom glands that impregnate their saliva. One is used to immobilize the hunted crustaceans before eating them. The second, tetrodotoxin, is used for defense and is found in several other sea creatures such as pufferfish. This toxin is a powerful neurotoxin with a strong paralyzing power. The bite is painless to humans but effects appear any time between 15-30 minutes and up to four hours, though the rate of onset of symptoms varies by individual, and children are more sensitive to the toxins.
The first phase of the poisoning is characterized by facial and extremity paresthesia, and the victim feels tingling and/or numbness on the face, tongue, lips and other body extremities. The victim may also suffer excessive sweating, severe headaches coupled with dizziness, speech problems, hypersalivation, moderate emesis, movement disorders, a feeling of weakness, cyanosis to extremities and lips and petechial hemorrhages on the body.
The second phase of poisoning usually occurs after eight hours and includes hypotension and generalized spastic muscle paralysis. Death may occur between 20 minutes and 24 hours after the onset of symptoms, usually resulting from respiratory paralysis. Throughout each of the phases of poisoning, the state of consciousness of the victim is unaffected.