The blue-lined octopus (Hapalochlaena fasciata) is one of four species[2] of highly venomous blue-ringed octopuses. It can be found in Pacific Ocean waters that stretch from Australia to Japan.[2] It is most commonly found around intertidal rocky shores and coastal waters to a depth of 15 metres (49 ft) between southern Queensland and southern New South Wales. It is relatively small, with a mantle up to 45 millimetres (1.8 in) in length. In its relaxed state, it is a mottled yellow-brown with dark blue or black streaks covering the whole body apart from the underside of its arms, but its vibrant blue markings appear as a warning to predators when it feels threatened.[3] Along with its other closely related species, the blue-lined octopus is regarded as one of the most dangerous animals in the sea, and its venom can be fatal to humans.[2]
Blue-lined octopuses tend to swim around shallow areas of coral reefs and tide pools.[4] They often hide in crevices of reefs, empty seashells, and other ocean resources they can find to conceal their identity.[4] They are diurnal creatures, hunting crabs and small fish during the day.[4] They do not use their venom (known as tetrodotoxin) to kill their prey, but instead trap it inside their arms and pierce them with its parrot-like beak.[4]
Blue-lined octopuses can be very lethal to humans. Their saliva contain a special neurotoxin called tetrodotoxin.[5] However, the species is more likely to flee and find shelter in an encounter due to their extremely shy nature.[3] Nonetheless, there have been at least three reported human deaths from the blue-lined octopus.[6] It poses most danger to those who pick up the octopus and physically touch it.[3]
If a human is to be attacked by the octopus, the injection may not be felt at first due to the small injection apparatus of the octopus.[3] After some time, symptoms of the injection include loss of feeling in the tongue/lips, muscle weakness/paralyzation, respiratory failure, unconsciousness, and eventually death.[3] The tetrodotoxin in blue-lined octopuses is so lethal that it has been estimated that the venom from a single 25-gram octopus can kill about ten 75-kilogram humans.[5]
The blue-lined octopuses start reproducing at a year old.[4] Males seek out female companions and then pounce on them. If they are successful, the female octopus will lay 50 to 100 eggs 30 days after the encounter.[4] During the 30 days, the female octopus hides her eggs under her arms and does not leave her hiding spot until the eggs hatch.[4] After laying her eggs, the female octopus dies.[4]
{{cite journal}}: CS1 maint: multiple names: authors list (link) {{cite journal}}: CS1 maint: multiple names: authors list (link) The blue-lined octopus (Hapalochlaena fasciata) is one of four species of highly venomous blue-ringed octopuses. It can be found in Pacific Ocean waters that stretch from Australia to Japan. It is most commonly found around intertidal rocky shores and coastal waters to a depth of 15 metres (49 ft) between southern Queensland and southern New South Wales. It is relatively small, with a mantle up to 45 millimetres (1.8 in) in length. In its relaxed state, it is a mottled yellow-brown with dark blue or black streaks covering the whole body apart from the underside of its arms, but its vibrant blue markings appear as a warning to predators when it feels threatened. Along with its other closely related species, the blue-lined octopus is regarded as one of the most dangerous animals in the sea, and its venom can be fatal to humans.
