At Axial Seamount, there are two common species of octopus, and at least one squid. These taxa all belong to Phylum Mollusca, Class Cephalopoda.
Graneledone Octopus (Graneledone boreopacifica)
The largest octopus observed at Axial Seamount, Graneledone boreopacifica, is very curious and fairly common on the lava rocks and at hydrothermal vent fields. It is not unique to Axial, as it is found in other Pacific deep sea environments. At Axial, these octopods seem to be attracted to the abundant vent fauna on which they prey. The octopus may also use the hard lava rock substrate found at Axial for laying their eggs.
Specimens off the Oregon coast have been measured at 43 cm (17 in), though Axial specimens are estimated at less than 40 cm.
Umbrella Octopus (Opisthoteuthis sp.)
Umbrella octopi are known for their curious way of getting around – by using a combination of pulsing their webbed arms, moving their fins, and jet propulsion through a funnel, some compare it to a parachute being unveiled. Little is known about the Opisthoteuthis, except that it resides in the mesopelagic zone – up to 500 meters below the surface of the ocean. The Opisthoteuthis averages 7 inches in diameter.
Cockatoo Squid (Taonius borealis)
The Cockatoo Squid is a deep sea member of the glass squids, found in the waters above Axial Seamount. These squid have sac-like bodies filled with ammonia to aid in their buoyancy. They also have a mass of tentacles above their heads that resemble a cockatiel’s crest, the basis of this squid’s common name. The Cockatoo Squid has large eyes that are capable of moving from a forward looking direction to either side of its head. Special light-emitting cells called photophores located under their eyes help the squid to be camouflaged by canceling out its silhouette. Cockatoo Squid can grow to 50cm (19.7in).