Gary Bell/ Oceanwide / Veined Octopus (Octopus marginatus), Anilao, Philippines

Gary Bell/ Oceanwide / Veined Octopus (Octopus marginatus) hiding in bottle, Anilao, Philippines

Gary Bell/ Oceanwide / Wonderpus Octopus (Wunderpus photogenicus), Anilao, Philippines

Gary Bell/ Oceanwide / Wonderpus Octopus (Wunderpus photogenicus), Anilao, Philippines

Gary Bell/ Oceanwide / Wonderpus Octopus (Wunderpus photogenicus), Anilao, Philippines

Gary Bell/ Oceanwide / Veined Octopus (Octopus marginatus) predating urchin, Anilao, Philippines

Gary Bell/ Oceanwide / Veined Octopus (Octopus marginatus) hiding in glass jar, Lembeh Strait, Indonesia

Alex Mustard / Free swimming mimic octopus (Thaumoctopus mimicus). Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Free swimming mimic octopus (Thaumoctopus mimicus). Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Veined octopus (Amphioctopus marginatus) shelters inside an old clam shell, with silver-sides in the water above. Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Veined octopus (Amphioctopus marginatus) emerging from its home in an old clam shell. Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Shane Gross / Larval Wonderpus octopus (Wunderpus photogenicus) drifting in the open ocean at night off Anilao, Philippines.

Shane Gross / Wonderpus octopus (Wunderpus photogenicus) in its juvenile or larval stage. At this stage it is transparent and drifts in the open ocean as plankton. Anilao, Philippines.

SCOTLAND: The Big Picture / Curled octopus (Eledone cirrhosa) amongst a horse mussel bed (Modiolus modiolus) Shetland, Scotland, UK, August.

John Chan / Western gull (Larus occidentalis) feeding on a California two-spot octopus (Octopus bimaculoides) on a mudflat at low tide, Southern California, USA, November.

David Fleetham / Day / Big blue octopus (Octopus cyanea) with diver in background. Hawaii. September 2012.

David Fleetham / Day / Common Reef Octopus (Octopus cyanea) swimming. Hawaii.

David Fleetham / Common reef octopus (Octopus cyanea), Hawaii.

Mark MacEwen / Octopus tree (Didiera madagascariensis), Spiny Forest, Berenty, Madagascar

Sue Daly / Barrel jellyfish (Rhizostoma octopus) swimming past, Sark, British Channel Islands, UK, September.

Alex Mustard / Veined octopus (Amphioctopus marginatus) sheltering in an old clam shell, with plankton swirling around it at night (captured as trails in the long exposure). Bitung, North Sulawesi, Indonesia. Lembeh...

SCOTLAND: The Big Picture / European river otter (Lutra lutra) female bringing octopus ashore for cub, Shetland, Scotland, UK, October.

Wim van den Heever / South African fur seal (Arctocephalus pusillus pusillus) bull breaking apart octopus. False Bay, Cape Town, South Africa.

Franco Banfi / Pacific octopus (Octopus dofleini) Vancouver Island, British Columbia, Canada, Pacific Ocean

Alex Mustard / Reef octopus (Octopus cyanea) portrait near wreck. Gubal Island, Egypt. Red Sea.

Solvin Zankl / Deepsea Octopus (Bathypolypus bairdii) specimen from the North Atlantic, near the Faroe Islands at a depth of 805m

Alex Mustard,Alex Mustard / Veined octopus (Amphioctopus marginatus) shelters in discarded coconut shell. Lembeh Strait, North Sulawesi, Indonesia. Molucca Sea.

Paul D Stewart / Illustration of Giant Octopus (Octopus dofleini) attacking a ship, 1815 copperplate engraving from Bertuch's 'Bilderbuch fur kinder' 16 plate 5. with contemporary colour. 'Colosal Polypus' (octopus) a...

Alex Mustard / The eye of a Pacific giant octopus (Enteroctopus dofleini). Browning Pass, Vancouver Island, British Columbia, Canada

Alex Mustard / Pacific giant octopus (Enteroctopus dofleini) hunts for food on a colourful reef in Browning Pass, Vancouver Island, British Columbia, Canada

Alex Mustard / Common Sydney octopus (Octopus tetricus) detail of eyes. Sydney Harbour. New South Wales, Australia

Solvin Zankl / Octopus (Octopus vulgaris), close up of eye, San Pietro Island, Sardinia, Italy, Mediterranean, July

Jeff Rotman / Close up of eye of Giant Pacific Octopus (Enteroctopus dofleini), British Columbia, Canada, Pacific Ocean.

Juergen Freund / Blue-ringed octopus (Hapalochlaena lunulata) swimming through water, Batangas, Philippines

Juergen Freund / Coconut / Veined octopus (Octopus marginatus) hiding in its shell home. Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Coconut / Veined octopus (Octopus marginatus) in a bottle cap getting a new shell to use as its home. Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Coconut / Veined octopus (Octopus marginatus) hiding in its bottle cap home, using a shell as a door. Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Coconut octopus / Veined octopus (Octopus marginatus) in its shell home. Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Coconut octopus / Veined octopus (Octopus marginatus) in its shell home. Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Coconut octopus / Veined octopus (Octopus marginatus) in its shell home. Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Coconut octopus / Veined octopus (Octopus marginatus) in its shell home. Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Coconut / Veined octopus (Octopus marginatus) hiding in its shell home. Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Tropical blue-ringed octopus (Hapalochlaena lunulata) hunting. Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Coconut / Veined octopus (Octopus marginatus) ready to flee from its coconut shell home. Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Coconut / Veined octopus (Octopus marginatus) in its shell home. Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Poison ocellate octopus (Octopus mototi) on seabed. Lembeh Strait, North Sulawesi, Indonesia

Juergen Freund / Coconut / Veined octopus (Octopus marginatus) ready to flee from its coconut shell home. Lembeh Strait, North Sulawesi, Indonesia.

Georgette Douwma / Wonderpus (Wunderpus photogenicus) octopus on sea bed, Lembeh Strait, North Sulawesi, Indonesia.

Wild Wonders of Europe / Zankl / Common octopus (Octopus vulgaris) close-up of eyes, Malta, Mediteranean, May 2009. WWE INDOOR EXHIBITION Wild Wonders kids book.

Wild Wonders of Europe / Sá / Octopus on rocks, Deserta Grande, Desertas Islands, Madeira, Portugal, August 2009

Wild Wonders of Europe / Banfi / Common octopus (Octopus vulgaris) in hole, Larvotto Marine Reserve, Monaco, Mediterranean Sea, July 2009

David Shale / Deepsea octopus (Benthoctopus johnsoniana) Mid-Atlantic Ridge, North Atlantic Ocean

David Shale / Deepsea octopus (Benthoctopus johnsoniana) Mid-Atlantic Ridge, North Atlantic Ocean

David Shale / Octopod {Grimpoteuthis discoveryi} Mid-Atlantic Ridge, North Atlantic Ocean

David Shale / View inside the mantle of the deepsea Octopod {Grimpoteuthis discoveryi} Mid-Atlantic Ridge, North Atlantic Ocean

Wild Wonders of Europe / Zankl / Common octopus (Octopus vulgaris) on rock, Malta, Mediteranean, May 2009

David Shale / Deepsea octopus (Grimpoteuthis sp), "Dumbo", North Atlantic.

Wild Wonders of Europe / Pitkin / Common octopus (Octopus vulgaris) hunting at night, Elephant Bay, Lavezzi Islands, Corsica, France, September 2008

Kevin Schafer / Ring-tailed Lemur (Lemur catta) in Octopus tree, Mantady National Park, Madagascar

Solvin Zankl / Atlantic longarm octopus (Octopus defilippi), Atlantic ocean

Solvin Zankl / Deepsea pelagic octopod (Vitreledonella richardi) Atlantic ocean.

Solvin Zankl / Close up of tentacles and suckers of a Deepsea octopus {Bolitaena pygmaea} Atlantic ocean

David Shale / Deepsea cirrate octopod (Stauroteuthis syrtensis) 830m, Gulf of Maine, Atlantic

David Shale / Deepsea cirrate octopod {Stauroteuthis syrtensis} 830m, Gulf of Maine, Atlantic

David Shale / Paper argonaut (Argonauta sp) Gulf of Mexico, deep sea species

David Shale / Deepsea octopus (Benthoctopus sp) mantle showing suckers, deep sea Atlantic oceandeep sea

Jeff Rotman / Giant Pacific octopus squirting ink at diver, British Columbia Canada

Fred Bavendam / Pacific Giant Octopus (Enteroctopus dofleini) squirting ink in defense as it jets away, Quadra Island, British Columbia, Canada

Fred Bavendam / Pacific Giant Octopus (Enteroctopus dofleini) female guarding her eggs, Quadra Island, British Columbia, Canada

Chris Newbert / Octopus (Octopus sp) portrait, underwater, Kona, Hawaii

Norbert Wu / California Bigeye Octopus (Octopus californicus) deep sea species swimming, California

Fred Bavendam / Pacific Giant Octopus (Enteroctopus dofleini) flaring out its arms as it settles to the ocean bottom after swimming, Quadra Island, British Columbia, Canada

Fred Bavendam / Pacific Giant Octopus (Enteroctopus dofleini) flaring out its arms as it prepares to drop to the ocean bottom after swimming, Quadra Island, British Columbia, Canada

Fred Bavendam / Pacific Giant Octopus (Enteroctopus dofleini) eggs and newborn, Victoria, British Columbia, Canada

Fred Bavendam / Pacific Giant Octopus (Enteroctopus dofleini) eggs and newborn, Victoria, British Columbia, Canada

Fred Bavendam / Paper Nautilus (Argonauta nodosa) is actually a pelagic Octopus, females make the parchment-like shell to carry incubating eggs, South Australia

Norbert Wu / California Two-spot Octopus (Octopus bimaculoides) juveniles hatch from egg cases, southern California

Norbert Wu / California Bigeye Octopus (Octopus californicus) swimming, southern California

Norbert Wu / California Bigeye Octopus (Octopus californicus) deep sea species swimming underwater, California

Fred Bavendam / Pacific Giant Octopus (Enteroctopus dofleini) scavenging on a dead Blue Dog (Squalus acanthias), Campbell River, British Columbia, Canada

Fred Bavendam / Pacific Giant Octopus (Enteroctopus dofleini) using its suction discs to hold two crabs it has caught, Quadra Island, British Columbia, Canada

Fred Bavendam / Pacific Giant Octopus (Enteroctopus dofleini) scurrying across the ocean floor as it forages for crabs, Quadra Island, British Columbia, Canada

Fred Bavendam / Pacific Giant Octopus (Enteroctopus dofleini) eggs, Victoria, British Columbia, Canada

Flip Nicklin / Octopus (Octopus sp) baby swimming through water column

Constantinos Petrinos / Veined octopus inside shell {Octopus marginatus}, Lembeh Strait, N Sulawesi, Indonesia. Shells are found in the seabed and dug up and cleaned by octopus, which then climbs inside for protection.

Constantinos Petrinos / Common octopus on sand, Greece

Georgette Douwma / Common reef / Day octopus hunting for crustaceans and fish, enclosing coral head with arms and webs, using the arm tips to flush out prey into waiting suckers {Octopus cyaneus} Andaman Sea, Thailand

Georgette Douwma / Common reef / Day octopus {Octopus cyaneus} at rest on coral reef Sipadan, Malaysia

Jeff Rotman / Octopus parachutes down on prey, Red Sea

Constantinos Petrinos / Veined / Marginated octopus {Octopus marginatus} holds crisp bag against back for protection. Lembeh, Sulawesi, Indonesia

Jeff Rotman / Diver films bottlenose dolphin playing with octopus. Egypt, Red Sea Model released.

Jeff Rotman / Octopus swimming in Red Sea. Egypt

Jeff Rotman / Giant Pacific octopus (Octopus dofleini) British Columbia Model released.

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

Alex Mustard / Bue ring octopus (Hapalochlaena lunulata) walking across the sea bed. Dauin, Dauin Marine Protected Area, Dumaguete, Negros, Philippines. Bohol Sea, tropical west Pacific Ocean.

Alex Mustard / Blue ring octopus (Hapalochlaena lunulata) walks across the sea bed. Dauin, Dauin Marine Protected Area, Dumaguete, Negros, Philippines. Bohol Sea, tropical west Pacific Ocean.