Many aquatic molluscs are present in Antarctica. Bivalves such as Adamussium colbecki move around on the seafloor, while others such as Laternula elliptica live in burrows filtering the water above.[6] There are around 70 cephalopod species in the Southern Ocean, the largest of which is the giant squid (Architeuthis sp.), which at 15 metres (49 ft) is the largest invertebrate in the world. Squid makes up the entire diet of some animals, such as grey-headed albatrosses and sperm whales, and the warty squid (Moroteuthis ingens) is one of the subantarctic's most preyed upon species by vertebrates.[23]