The Bigfin Squid, a member of the genus Magnapinna, is a confirmed resident of the deep ocean, despite its strange appearance and extreme rarity. Its existence has been cemented not by capturing adult specimens, but through the steady accumulation of technological evidence. This mysterious cephalopod highlights how much of our planet’s biodiversity remains hidden beneath the surface, far from human observation.
Documented Sightings and Confirmation
The first hint of this creature’s existence came not from a live sighting but from physical specimens that were damaged or immature. The family Magnapinnidae, which the Bigfin Squid belongs to, was formally established in 1998 by researchers Michael Vecchione and Richard Young, based on juvenile and paralarval specimens collected over decades. These early specimens, including one caught off the Azores in 1883, already displayed the proportionally large fins that give the genus its name, which translates to “great fin.”
The definitive confirmation of the Bigfin Squid’s adult form came primarily through advancements in deep-sea technology, specifically the use of submersibles and Remotely Operated Vehicles (ROVs). The earliest confirmed visual observation occurred in 1988 off the coast of northern Brazil at a depth of 4,735 meters. A later, widely publicized sighting in 2001, filmed by a Shell Oil company ROV in the Gulf of Mexico, provided clear footage of the creature’s distinctive posture.
These video observations allowed scientists to link the strange, long-limbed adults to the small, large-finned juvenile specimens previously studied. In 2021, a NOAA Ocean Exploration expedition captured clear footage of an adult Bigfin Squid at 2,385 meters off the West Florida Escarpment. The collective evidence from these rare encounters, which total only about two dozen confirmed in situ sightings globally, establishes the Bigfin Squid as a real and widely distributed species.
Distinctive Physical Characteristics
The Bigfin Squid is immediately recognizable by its unique morphology. The creature’s defining feature is its pair of large fins, which can measure up to 90% of the mantle length, giving the squid a distinctive, almost ear-like appearance. These fins are the source of the genus name Magnapinna and are used for slow, graceful movement through the water column.
Extending from the small, gelatinous body are the Bigfin Squid’s ten appendages: eight arms and two tentacles, which are virtually indistinguishable in presumed adults. These appendages are long and thin, resembling fine, elastic filaments that trail far below the mantle. The length of these filaments is immense, estimated to be between 15 and 20 times the length of the squid’s mantle, or body tube.
This extreme proportion means that most of the animal’s total size is made up of its limbs, with total lengths estimated to be between 4 and 8 meters (13 to 26 feet) for larger individuals. The appendages also feature a characteristic bend, held out perpendicular to the body before dropping straight down, creating a visual effect often referred to as “elbows.” This posture, along with microscopic suckers lining the filaments, suggests the squid may use its arms as a passive net to capture prey drifting in the water.
Deep-Sea Habitat and Rarity
The Bigfin Squid’s elusiveness is directly tied to its preferred environment: the vast, dark expanse of the deep ocean. These animals inhabit the bathypelagic and abyssopelagic zones, generally found at depths ranging from 1,000 meters down to beyond 6,000 meters. A record observation in the Philippine Trench confirmed a Bigfin Squid at an astounding depth of 6,212 meters (over 20,300 feet), establishing it as the deepest-dwelling squid known.
The tremendous pressure and complete absence of sunlight at these depths make the habitat extremely challenging for human observation, which explains the creature’s rarity. All confirmed sightings have required specialized deep-sea equipment like ROVs and submersibles. Despite the scarcity of observations, the locations of these sightings—spanning the Atlantic, Pacific, and Indian Oceans—suggest the Bigfin Squid has a wide, cosmopolitan distribution. Much remains unknown about the Bigfin Squid’s life history, diet, and population size due to the logistical difficulties of studying life in this deep environment.