Jeff Rotman / Giant Pacific octopus (Octopus dolfeini) jets away. British Columbia Model released.

Alex Mustard / Paper nautilus (Argonauta hians) attaches onto a piece of plastic in open water at night. Anilao, Batangas marine protected area, Luzon, Philippines. Verde Island Passages, Tropical West Pacific Ocean...

Alex Mustard / Long exposure of a bigfin reef squid (Sepioteuthis lessoniana) in open water at night. Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea..

Sergio Hanquet / Cuttlefish (Sepia officinalis) feeding on Scorpionfish (Scorpaenidae). Tenerife, Canary Islands.

David Fleetham / Common / Day Octopus (Octopus cyanea) and diver. Hawaii. Model released.

David Fleetham / Rock Shrimp (Urocaridella antonbrunii) on a Common Octopus (Octopus cyanea). Tulamben, Bali, Indonesia.

David Fleetham / Reef scene with a Broadclub Cuttlefish (Sepia latimanus) Komodo, Indonesia. Two images were digitally stitched together to create this panorama.

David Fleetham / Male Oval / Big Fin Reef Squid Squid (Sepioteuthis lessoniana) against dark background. Hawaii.

David Fleetham / Short armed sand octopus (Amphioctopus arenicola) lives in a small hole on sandy seabed, endemic, Maui, Hawaii.

David Fleetham / Male Big fin reef / Oval squid (Sepioteuthis lessoniana), which can reach 14 inches in length. Hawaii.

David Fleetham / Male Big fin reef / Oval squid (Sepioteuthis lessoniana), which can reach 14 inches in length. Hawaii.

David Fleetham / Eye of Papuan cuttlefish (Sepia papuensis). Tulumben, Bali, Indonesia.

David Fleetham / Mating Papuan cuttlefish (Sepia papuensis) Tulumben, Bali, Indonesia.

David Fleetham / Caribbean reef squid (Sepioteuthis sepioidea), Caribbean.

David Fleetham / Caribbean reef squid (Sepioteuthis sepioidea) in shallow waters off the Caribbean.

David Fleetham / Veined octopus (Octopus marginatus) using discarded bottle for a home, Anilao, Philippines.

David Fleetham / Male Common reef octopus (Octopus cyanea), on right, passing sperm to the female. Tubbatah Reef, Philippines.

David Fleetham / Tropical blue-ringed octopus (Hapalochiaena lunulata) swimming over seabed, Philippines.

David Fleetham / Mimic octopus (Thaumoctopus mimicus) camouflaged on seabed, Philippines.

David Fleetham / Broadclub cuttlefish (Sepia latimanus) on coral reef, Komodo, Indonesia.

David Fleetham / Tropical blue-ringed octopus (Hapalochiaena lunulata) Komodo, Indonesia.

David Fleetham / Bobtail squid (Euprymna berryi), Komodo, Indonesia.

David Fleetham / Stumpy spined cuttlefish (Sepia bandensis) feeding on mantis shrimp at night, Rinca Island, Komodo National Park, Indonesia.

David Fleetham / Giant Pacific octopus (Octopus dofleini) and a diver off Keystone Jetty, Whidbey Island, Washington, USA. Model released

David Fleetham / Divers on underwater scooters and a common cuttlefish (Sepia officinalis) in Palau, Micronesia, January 2005. Model released

David Fleetham / Starry night octopus (Octopus luteus) on seafloor, Komodo, Indonesia.

David Fleetham / Two spot octopus (Octopus bimaculatus), camouflaged against reef, California, USA.

David Fleetham / Southern calamary / reef squid (Sepioteuthis australis), Australia.

David Fleetham / Broadclub cuttlefish (Sepia latimanus), Komodo, Indonesia.

David Fleetham / Bobtail squid (Euprymna berryi) Komodo, Indonesia.

David Fleetham / Bottletail squid (Sepiadarium kochi), Komodo, Indonesia.

David Fleetham / Caribbean reef squid (Sepioteuthis sepioidea) near Bonaire Island, Caribbean.

David Fleetham / Caribbean reef squid (Sepioteuthis sepioidea) near Bonaire Island, Caribbean.

David Fleetham / Day / common reef octopus (Octopus cyanea), on coral reef, Hawaii.

Ingo Arndt / Close up of suckers on tentacle of Octopus {Octopus sp}

Alex Mustard / Coconut / Veined octopus (Amphioctopus marginatus) hunts in the sand at night, while illuminated by a diver's torch beam, Anilao, Batangas, Luzon, Philippines. Verde Island Passages, Pacific Ocean.

Franco Banfi / Squid (probably brought to surface by Sperm whale) and Sperm whale (Physeter macrocephalus) Dominica, Caribbean Sea, Atlantic Ocean. Vulnerable species.

SCOTLAND: The Big Picture / European river otter (Lutra lutra) female bringing an octopus (Octopoda) ashore for her cubs, Shetland, Scotland, UK, November.

Jeff Rotman / Fisherman holding Humboldt squid (Dosidicus gigas) Chile, February 2016.

Paul D Stewart / Shell of extant deep water squid Spirula (Spirula spirula) backlit and sectioned to show how the structure of partitions within the shell is reminiscent of the extinct ammonites and living nautiloids.

Paul D Stewart / Historical illustration of Common octopus (Octopus vulgaris) Pierre Denys de Montfort engraving from 'Histoire Naturelle Generale et Particuliere des Mollusques', 1801-1802.

Paul D Stewart / Giant squid (Architeuthis ) illustration in 'The Cephalopods of the North-Eastern Coast of America' by A.E. Verrill, Transactions of the Connecticut Academy of Sciences, vol. 5, Dec. 1879

Pascal Kobeh / Common reef octopus (Octopus cyanea) resting at night, Palau. Philippine Sea.

Pascal Kobeh / Eye of a Broadclub cuttlefish (Sepia latimanus) at night, Palau. Philippine Sea.

Pascal Kobeh / Broadclub cuttlefish (Sepia latimanus) at night, Palau. Philippine Sea.

Pascal Kobeh / Broadclub cuttlefish (Sepia latimanus) at night, holding in its tentacles prey, Manado, Indonesia. Sulawesi Sea.

Pascal Kobeh / Broadclub cuttlefish (Sepia latimanus) at night, holding prey, Manado, Indonesia. Sulawesi Sea.

Pascal Kobeh / Common reef octopus (Octopus cyanea) Baja California peninsula, Mexico. Sea of Cortez.

Pascal Kobeh / Diver close to a Pharaoh cuttlefish (Sepia pharaonis), Daymaniyat islands, Oman. Gulf of Oman. October 2010.

Pascal Kobeh / Two Pharaoh cuttlefish (Sepia pharaonis) mating, Daymaniyat islands, Oman. Gulf of Oman.

Pascal Kobeh / Two Pharaoh cuttlefish (Sepia pharaonis) after mating. The male is on female to protect her from potential rivals till she lays her eggs, Daymaniyat islands, Oman. Gulf of Oman.

Pascal Kobeh / Two Pharaoh cuttlefish (Sepia pharaonis) after mating. The male is on female to protect her from potential rivals till she lays her eggs, Daymaniyat islands, Oman. Gulf of Oman.

Pascal Kobeh / Undeterminate octopus (Octopus ) on sea floor, Manado, Indonesia. Sulawesi Sea.

Franco Banfi / Broadclub cuttlefish (Sepia latimanus) on the surface between mangrove's leaves, at exploratory dive, Blue water mangrove, Raja Ampat, Irian Jaya, West Papua, Indonesia, Pacific Ocean

Franco Banfi / Common Cuttlefish, (Sepia officinalis) The Cave diving site, Vis Island, Croatia, Adriatic Sea, Mediterranean

Franco Banfi / Scuba diver and Common Cuttlefish (Sepia officinalis) The Cave dive site, Vis Island, Croatia, Adriatic Sea, Mediterranean

Franco Banfi / Octopus (Octopus vulgaris) with eggs, Ischia Island, Italy, Tyrrhenian Sea, Mediterranean

Franco Banfi / Reaper cuttlefish (Sepia mestus) Raja Ampat, Irian Jaya, West Papua, Indonesia, Pacific Ocean

Franco Banfi / Reaper cuttlefish (Sepia mestus) Raja Ampat, Irian Jaya, West Papua, Indonesia, Pacific Ocean

Juergen Freund / Pygmy cuttlefish pair (Sepia bandensis) Raja Ampat, West Papua, Indonesia

Juergen Freund / Pygmy cuttlefish pair (Sepia bandensis) Raja Ampat, West Papua, Indonesia

Juergen Freund / Pygmy cuttlefish pair (Sepia bandensis) Raja Ampat, West Papua, Indonesia

Juergen Freund / Pygmy cuttlefish (Sepia bandensis) Raja Ampat, West Papua, Indonesia

Jabruson / Young fisherman holding a catch of Indian Squid (Loligo / Uroteuthis duvaucelli) underwater to keep them fresh until ready for delivery to the fish market in Shimoni on the south coast of Kenya, Febru...

Jabruson / Muslim Fisherman holding a catch of White-spotted Octopus (Octopus macropus) whilst waiting with his wife for boat transport to Shimoni fish market, Wasini Island off the coast of Kenya, February 2011

Franco Banfi / Octopus (Octopus vulgaris) male, Maldives, Indian Ocean

Doug Perrine / Juvenile Arrow Squid (probably Loligo plei), showing chromatophores (colored pigment sacs) at night. Lighthouse Reef Atoll, Belize, Central America.

Sue Daly / Little Cuttlefish / Bobtail Squid (Sepiola atlantica). Maseline harbour, Sark, British Channel Islands, October.

Sue Daly / Little Cuttlefish / Bobtail Squid (Sepiola atlantica). Maseline harbour, Sark, British Channel Islands, October.

Sue Daly / Common Cuttlefish (Sepia officinalis). Maseline Harbour, Sark, British Channel Islands, September.

Juan Manuel Borrero / Illustration of internal Nautilus anatomy. Pencil and watercolor painting.

Sue Flood / Octopus for sale in fish market, Otaru, Hokkaido, Japan. Otaru is one of Hokkaido's key ports, and serves the nearby city of Sapporo and is famous for its Sushi, June 2012

Linda Pitkin / 2020VISION / Pink sea fan / Warty coral (Eunicella verrucosa) with attached eggs of a Common squid (Loligo vulgaris), eggcase of a Lesser-spotted dogfish (Scyliorhinus canicula), and Spiny starfish (Marthasterias...

Alex Mustard / A Caribbean reef octopus (Octopus briareus) swimming through spawning Sea rods (Pseudoplexaura) at night, East End, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Jeff Rotman / Common reef octopus (Octopus cyanea) with diver observing, Eilat, Israel, Red Sea. Model released. January 2011 Model released.

Jeff Rotman / Common reef octopus (Octopus cyanea) camouflaged on coral reef, Eilat, Israel, Red Sea

Solvin Zankl / The Tail-Light Squid Shell (Spirula spirula) has a chambered, delicate shell, with diameter of about 1 cm from Raja Ampat, Indonesia. Digital focus stacking image

Solvin Zankl / GEOMAR / Bobtail squid (Rossia glaucopis) from Trondheimfjord, North Atlantic Ocean, Norway. Photo taken in cooperation with GEOMAR coldwater coral research project

Alex Mustard / Common reef / day octopuses (Octopus cyanea) courting. The male, on the right, is rearing up and showing his mouth and tentacles, while still maintaining contact with the female. This is a rarely seen...

Alex Mustard / Common reef / day octopuses (Octopus cyanea) mating. The male, on the right, it passing his sperm to the female, on the left, by placing it under her mantle. His arm is visible on her body next to her...

Alex Mustard / Tropical blue ring octopus (Hapalochlaena lunulata) is small but has one of the most venomous creatures in the ocean, its bite injects a neurotoxin that paralyses its victim. It flashes its blue rings...

Alex Mustard / A blue ring octopus (Hapalochlaena lunulata) flashes its blue rings as it crawls over a coral reef. Kapalai Island, Sulu Sea, Sabah, Borneo, Malaysia..

Alex Mustard / Striped pyjama squid (Sepioloidea lineolata) hovers above the seabed. Gulf St Vincent Edithburgh, Yorke Peninsular, South Australia, Australia

Alex Mustard / Common Sydney octopus (Octopus tetricus) peers out from its den. Sydney Harbour, New South Wales, Australia.

Alex Mustard / Two spotted octopus (Octopus bimaculatus) moves across rocks. Revillagigedos Islands, Mexico.

Alex Mustard / A pair of mimic octopus (Thaumoctopus mimicus) mating. The male, behind, has grabbed the female and grasps her as he tries to place his sperm sac inside her mantle with his arm. Lembeh Strait, Molucca...

Alex Mustard / A pair of mimic octopus (Thaumoctopus mimicus) mating/courtship. The smaller male, right, is riding on top of the female as he tries to place his sperm sac inside her mantle with his arm. Lembeh Strai...

Alex Mustard / Pfeffer's flamboyant cuttlefish (Metasepia pfefferi) hovers just above the seabed. The largest individuals of this species, such as this one, are not as brightly coloured as the younger ones. Lembeh S...

Alex Mustard / A veined octopus (Amphioctopus marginatus) peers out from a discarded plastic bottle. Lacking a skeleton, octopuses can squeese their bodies into the smallest spaces and through the tiniest holes. Lem...

Alex Mustard / Tropical blue ringed octopus (Hapalochlaena lunulata) free swims just above the seabed. Lembeh Strait, Molucca Sea Sulawesi, Indonesia

Alex Mustard / A young veined octopus (coconut octopus: Amphioctopus marginatus) shelters in an empty bivalve shell by pulling the two halves together with its arms. Lembeh Strait, Molucca Sea, Sulawesi, Indonesia.

Alex Mustard / Pfeffer's flamboyant cuttlefish (Metasepia pfefferi) walks across the seabed using special flaps on the underside of its body, and its outermost arms as four legs. This species rarely swims. Lembeh St...

Alex Mustard / Pfeffers's flamboyant cuttlefish (Metasepia pfefferi) displays on the seabed. Lembeh Strait, Molucca Sea, North Sulawesi, Indonesia, South East Asia

Alex Mustard / A common reef octopus (Octopus cyanea) foraging attracts several large reef fish, hoping to get an easy meal. Octopuses may try to hit fish with their arms to scare them off. Cannibal Rock, Sawu Sea,...

Alex Mustard / A common cuttlefish (Sepia officinalis) above seagrass meadow (Posidonia oceanica). Xlendi Bay, Gozo Island, Malta, Mediterranean Sea.

Alex Mustard / A diver encounters a common cuttlefish (Sepia officinalis) above seaweeds, Xlendi Bay, Gozo Island, Malta, Mediterranean Sea. June 2012, Model released