It is believed that this is due to the abiotic and biotic factors in relation to the depths at which they are found.

[1] It was formerly described as its own species, but was synonymised with the bigeye sixgill shark (Hexanchus nakamurai).

However, a study published in 2019 resurrected the species on the basis of molecular data.

[1][2] The Atlantic sixgill shark (Hexanchus vitulus) becomes sexually mature at around 1.40 to 1.75 meters.

[3] Their diet consists mainly of bony fish and cephalopods, with crustaceans sometimes included.