Blue-lined octopus

The blue-lined octopus (Hapalochlaena fasciata) is one of four species^[1] of highly venomous blue-ringed octopuses. It can be found in Pacific Ocean waters that stretch all the way from Australia to Japan^[1]. 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 they feel threatened^[2]. 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^[1].

Behavior

Blue lined octopuses tend to swim around shallow areas of coral reefs and tide pools.^[3]They often hide in crevices of reefs, empty seashells, and other ocean resources they can find to conceal their identity.^[3] They are diurnal creatures, hunting on crabs and small fishes during the day^[3]. They do not use their venom (known as tetrodotoxin) to kill their prey, but instead trap it inside their arms and pierce them with it's parrot-like beak.^[3]

Lethality

Blue lined octopuses can be very lethal to humans. Their saliva contain a special neurotoxin called tetrodotoxin^[4]. However, the species is more likely to flee and find shelter in an encounter due to their extremely shy in nature.^[2] Nonetheless, there have been at least three reported human deaths from the blue lined octopus.^[5] It poses most danger to those who pick up the octopus and physically touch it^[2].

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^[2]. After some time, symptoms of the injection include loss of feeling in the tongue/lips, muscle weakness/paralyzation, respiratory failure, unconsciousness, and eventually death.^[2] The tetrodotoxin in blue lined octopuses is so lethal that it’s been estimated that the venom from a single 25 gram octopus can kill about ten 75 kilogram humans.^[4]

Reproduction The blue lined octopuses start reproducing after a year of birth^[3]. 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.^[3] During the 30 days, the female octopus hide her eggs under her arms and does not leave her hiding spot until the eggs hatch.^[3] After laying her eggs, the female octopus dies.^[3]

References