The life cycle of the southern blue-ringed octopus, from mating through to the eggs hatching and the young reaching maturity, lasts for approximately seven months. The eggs are carried by the female throughout their development, which lasts for around two months, and the female does not eat during this time. Once hatched, the young grow rapidly and begin hunting live prey within one month (6). Young southern blue-ringed octopuses are thought to be venomous from birth (2), and their blue rings appear when they are about six weeks old (6).
This species reaches sexual maturity at just four months old (3) (6), and may begin laying eggs a month after that. The adult female southern blue-ringed octopus dies shortly after the eggs have hatched (6), and both sexes are unlikely to live for more than one year (3).
Like all cephalopods, the southern blue-ringed octopus is an active predator (2). This species is equipped with powerful venom which is secreted from the posterior salivary glands and is used to immobilise and kill the octopus’s prey of crabs and other crustaceans (2) (3) (6). The southern blue-ringed octopus may also consume small fish (2) (3).
Despite the southern blue-ringed octopus’s small size, its bites have been known to cause human fatalities (3) (5) (7), and the soft tissues of this species are also extremely poisonous if consumed (4). There is no antidote to the octopus’s venom (3) (5), but this species is not generally aggressive, preferring to hide rather than confront a potential attacker (2) (3).
Like other cephalopods, the southern blue-ringed octopus is considered to be one of the most intelligent of all invertebrates (2) (8).