There are at least 10 species of tiny blue-ringed octopuses, which, ironically for their size, are the most deadly of all cephalopods. Two well-known examples are the lesser Southern blue-ringed octopuses, Hapalochlaena maculosa Hoyle, , and the greater blue-ringed octopuses, Hapalochlaena lunulata , Quoy and Gaimard, The common name comes from the bright blue rings that appear when they are alarmed. Lesser Southern blue-ringed octopuses, Hapalochlaena maculosa , are the larger of the two and more common. They weigh only 28 grams with bodies to 5 cm long and arms to 10 cm.
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The southern blue-ringed octopus Hapalochlaena maculosa is one of three or perhaps four highly venomous species of blue-ringed octopuses. It is most commonly found in tidal rock pools along the south coast of Australia. They are normally a docile species, but they are highly venomous , possessing venom capable of killing humans.
Their blue rings appear with greater intensity when they become aggravated or threatened. The blue-ringed species are known for their small size, yet the southern variety is hailed as the largest of the genus. As a result, they have been classified as their own species. From arm to arm, most of these octopuses are no larger than 20 centimeters. This is larger by roughly 5 centimeters on average with other varieties of the blue-ringed octopus.
When at peace, their coloring is often a drab, mucus like color. However, once it feels sufficiently threatened, the eponymous blue-rings suddenly appear. These octopuses have an average of about 60 rings that have multilayer reflectors that allow them to flash a blue green color. Like other species of the blue-ringed octopus, this variety is named for the vibrant blue rings that it displays when agitated. Found along the southern coasts of Australia, H. In addition, the octopus enjoys a proximity to the plentiful forests of seagrass.
Despite their highly toxic venom, southern blue-ringed octopuses tend to be passive and relatively harmless unless provoked. They generally only use their toxins when hunting or when provoked. These creatures are nocturnal, primarily active at night. In addition, it was found that southern blue-ringed octopuses have at least slightly more acute olfaction smell sense which may affect choice in mate see Breeding, below. The prey of H. It pins down and injects it through its beak. This totally paralyzes its prey, often killing it outright.
This readies it for feeding. Another tactic it uses to hunt is releasing its venom as a mist into a location where its prey is commonly found. Their prey swim into the venom and become paralyzed, allowing for an attack.
The average life span of a southern blue ringed octopus is around seven months. The octopus reaches sexual maturity at around four months old, at which time it focuses its last few months of life towards copulation and breeding.
Both genders of this species are promiscuous, as they only have a limited set of gametes. The mating ritual of H. For this type of octopus, there is approximately a two-month window in which a female acquires and stores sperm from multiple males. During this time period, the mother rarely moves unless disturbed. When she is forced to move, she uses only two arms for locomotion.
The female also does not eat during this time period. Because of this, the mother dies shortly after the eggs have hatched. It is highly unlikely that the male or female would live beyond one year.
This unusual octopus maternal care system seems to be an advanced evolutionary development of the species. While this may seem strange, females only reproduce once in their lifetime,  so it is vital to them that their egg clutch survives. Once hatched, the H. The southern blue-ringed octopus also differs from other marine invertebrates in that there is no planktonic stage.
It was found in a study by Morse and Zenger that as size of the octopus increased, so too did willingness to mate. It is also possible females use some form of refined sense of smell to single out attractive mates.
Many studies have been done on how southern blue-ringed octopuses choose their mates and if females can choose the sperm used to fertilize her eggs Morse et al. Researchers have hypothesized that there may be cryptic female choice or sperm competition Morse et al.
The same study also found that males would spend less time mating with females that they had already mated with. What makes this octopus famous is its venom. Saliva glands of the southern blue-ringed octopus produce the deadly neurotoxin, maculotoxin. This may provide the toxin into its bloodstream. The toxin has also been found in the eggs of this octopus. The method of poisoning is still not fully understood, but it is assumed that H.
It is fatal to humans. Various references in popular culture depict the southern blue-ringed octopus as a nefarious seadevil lying in wait to attack humans with its deadly toxins. In actuality, the venom is primarily used in hunting or for defense. There are no reported cases of unprovoked aggression towards humans.
No antivenom exists. There are currently no known conservation efforts for the southern blue-ringed octopus. This being said, it is likely that H. It is also suggested that because the dispersal ability of H. From Wikipedia, the free encyclopedia. Hoyle , The Journal of Experimental Biology. Guide to Squid, Cuttlefish and Octopuses of Australasia. Csiro Publishing. Journal of Molluscan Studies. Retrieved Animal Behaviour.
Hapalochlaena maculosa in Blairgowrie, Victoria. Hapalochlaena Robson , Hapalochlaena maculosa Hoyle ,
Southern Blue Ringed Octopus
Found most commonly in the tidal rock pools along the southern coast of Australia. Most commonly found in rocky, shallow pools of water or in shallow corals. Also found under rocks in sandy or muddy stretches of bottom where alga is plentiful. Particularly common after storms when it can be found looking for crabs and bivalves. Moynihan , Campbell , Australian wildlife lectures , Rogerson , Park The blue-ringed octopus is a small octopus that ranges in size from 4 mm at birth to up to 20 cm in adulthood.
Southern blue-ringed octopus
The southern blue-ringed octopus Hapalochlaena maculosa is one of three or perhaps four highly venomous species of blue-ringed octopuses. It is most commonly found in tidal rock pools along the south coast of Australia. They are normally a docile species, but they are highly venomous , possessing venom capable of killing humans. Their blue rings appear with greater intensity when they become aggravated or threatened. The blue-ringed species are known for their small size, yet the southern variety is hailed as the largest of the genus. As a result, they have been classified as their own species.