They’re beautiful, tragic and sometimes brutal. Octopuses are among the ocean’s most fascinating and enigmatic creatures.
Octopus facts
Octopuses are similar to squid – but without the tentacles
Octopuses and squid both have eight arms, but a squid also has two tentacles with suckers to hunt fish and shrimp.
Some octopuses punch fish
Usually a solitary creature, Octopus cyanea can sometimes take part in multi-species hunting groups, a recent study revealed. They work with other fish species to find prey, but if other individuals catch prey without helping to find or flush it out of its hiding spot, the octopus will punch the cheaters with its arms.
There’s only one truly lethal octopus
Although there are several potentially deadly octopuses with venom, the blue-ringed octopus is the only major threat to humans, with venom a thousand times stronger than cyanide.
Many deep-sea octopuses die after brooding their eggs
The deep-sea octopus, Graneledone boreopacifica, will lay just one bunch of eggs in her lifetime – and will die once its brooding period is over. This is most likely due to starvation, as she won’t have eaten for the entire brooding period. This is the case for most octopuses, but for deep-sea octopuses the famine is much longer. In fact, many female octopuses die after reproducing because of this.
Male blue-lined octopuses inject females with venom before sex
Like other types of blue-ringed octopus, the blue-lined octopus is venomous. New research has shown that another surprising use of venom within this species is during sex, in which male octopuses inject females with venom before mating to avoid being cannibalised during reproduction.
There’s a nearly entirely transparent species of octopus
The glass octopus gets its name from its ability to be almost completely transparent – with only its optic nerve, eyeballs and digestive tract visible.
The world’s largest octopus is the giant Pacific octopus
The aptly named giant Pacific octopus (Enteroctopus dofleini) is the world’s biggest octopus species, with an average arm span of just over 4m.
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