Invertebrates
Vulcanoctopus
Vulcanoctopus hydrothermalis · also called vent octopus
Stripped of the ink sac and colour-changing skin most octopuses rely on for defence, Vulcanoctopus has instead adapted to a life spent entirely around hydrothermal vents, the only known octopus species specialised for this uniquely extreme corner of the deep sea.
Overview
Vulcanoctopus, Vulcanoctopus hydrothermalis, is a specialised carnivorous octopus native to hydrothermal vent habitat recorded along the East Pacific Rise. Its status as the only known vent-specialised octopus, loss of the usual ink-based defence, and reduced colour-changing ability make it one of the most ecologically unusual octopus species found anywhere in the ocean.
An octopus that gave up its usual defences
Where nearly every other octopus relies heavily on ink and rapid colour change to escape predators, Vulcanoctopus has lost much of both, a trade-off that only makes sense in a habitat where the usual threats those defences evolved against are far less pressing.
Status
Not Evaluated, known only from a limited number of naturally patchy hydrothermal vent sites now of interest for deep-sea mining.
Vulcanoctopus: common questions
Why doesn't Vulcanoctopus have an ink sac?
This species lacks the ink sac most other octopuses use for defence, an adaptation thought to reflect reduced predation pressure in its specialised hydrothermal vent habitat, where the usual threats octopuses evolved ink to escape may be less common.
Can Vulcanoctopus change colour like other octopuses?
Only to a limited degree, this species has a much-reduced capacity for the rapid skin colour changes typical of most octopuses, again likely linked to the limited predation risk of its unusual, specialised environment.
Is Vulcanoctopus the only octopus found at hydrothermal vents?
It is the only known octopus specifically adapted to life around hydrothermal vents, unlike other octopus species, which are found across a much broader range of ocean habitats away from vent activity.
What does Vulcanoctopus eat?
This species is a carnivore feeding on small crustaceans such as amphipods and copepods that themselves gather near hydrothermal vent openings, feeding within the same chemical-rich zone that supports the surrounding vent community.