Giant cuttlefish

The giant cuttlefish (Ascarosepion apama), also known as the Australian giant cuttlefish, is the world's largest cuttlefish species, growing to 50 cm (20 in) in mantle length and up to 100 cm (39 in) in total length (that is, including outstretched tentacles). They can weigh over 10.5 kg (23 lb). Like all cuttlefish species, the giant cuttlefish has eight arms and two feeding tentacles, as well as blue blood and three hearts. Using cells known as chromatophores, the cuttlefish can put on spectacular displays, changing colour in an instant. The giant cuttlefish is native to temperate and subtropical waters of Australia, from Brisbane in Queensland to Shark Bay in Western Australia and Tasmania to the south. It occurs on rocky reefs, seagrass beds, and sand and mud seafloor to a depth of 100 m (330 ft). The genetically distinct population in the Upper Spencer Gulf is the most studied population, and has become a tourist attraction.