Juergen Freund / Land Hermit crab using a plastic bottle cap as its home. Kavieng, Papua New Guinea, June 2010

Juergen Freund / Hermit crab with shell covered in soft coral (Heteroxenia fuscescens) Lembeh Strait, North Sulawesi, Indonesia

Wild Wonders of Europe / Lundgren / Hermit crab (Pagurus pubescens) on Kelp, Saltstraumen, Bod, Norway, October 2008

Chris Newbert / Right-handed Hermit Crab (Paguritta sp) colony in Hump Coral (Porites sp), Solomon Islands

Chris Newbert / Hermit Crab (Paguritta gracilipes) in Hump Coral (Porites sp) 30 feet deep, Solomon Islands

Alex Mustard / Portrait of Morgan's coral hermit crab (Paguritta morgani) looking out of its burrow in a hard coral colony. These hermit crabs are sedentary, remaining in their burrows, rather than carrying arou...

David Hall / Anemone hermit crab (Dardanus pedunculatus) carrying Anemones (Calliactis polypus) on shell. Mutualism in which anemones are transported to new feeding opportunities whilst providing camouflage and de...

Magnus Lundgren / Wild Wonders of China / Red hermit crab (Dardanus megistos) Xiaoliuqiu Island, Taiwan

Magnus Lundgren / Wild Wonders of China / Anemone hermit crab (Dardanus pedunculatus) Xiaoliuqiu Island, Taiwan

Pascal Kobeh / Coral hermit crab (Paguritta / Orthopagurus harmsi), Sulu sea, Philippines

SCOTLAND: The Big Picture / Hermit crab (Pagurus bernhardus) on yellow sponge, Loch Etive, west coast of Scotland, UK, September.

SCOTLAND: The Big Picture / Hermit crab (Pagurus bernhardus) sat on yellow sponge, Loch Etive, west coast of Scotland, UK, August.

Pascal Kobeh / Coral hermit crab (Dardanus pedunculatus) with sea anemones on its shell - the anemones get better feeding opportunities from extra mobility, the crab gains extra protection. Sulu Sea, Philippines.

Pascal Kobeh / Coral hermit crab (Dardanus pedunculatus) with sea anemones on its shell - the anemones get better feeding opportunities from extra mobility, the crab gains extra protection. Sulu Sea, Philippines. Me...

David Fleetham / Hermit crab (Dardanus pedunculatus) with Sea anemones (Calliactis polypus) for protection. Tulamben, Bali, Indonesia.

Alex Mustard / Hermit crab (Pagurus bernhardus) on a chalk nodule on a chalk reef. Sherringham, north Norfolk, England, United Kingdom. North Sea

David Fleetham / White spotted hermit crab (Dardanus megistos) amongst coral. Kauai, Hawaii.

Piotr Naskrecki / Hermit Crab (Coenobita sp), Vamizi Island, Mozambiqiue

Piotr Naskrecki / Hermit Crab (Coenobita sp), Vamizi Island, Mozambiqiue

Piotr Naskrecki / Hermit Crab (Coenobita sp), Vamizi Island, Mozambiqiue

David Fleetham / Coral hermit crab (Paguritta sp) in coral home, Yap, Micronesia. Small repro only

David Fleetham / Eye stalks and antennae of a hermit crab (Dardanus lagopodes) off the island of Yap, Micronesia.

Olga Kamenskaya / Hermit crab (Pagurus sp ) Novaya Zemlya, Russian Arctic, July

Olga Kamenskaya / Hermit crab (Pagurus sp.) Novaya Zemlya, Russian Arctic, July

Claudio Contreras / Staghorn hermit crab (Manucomplanus varians) and Staghorned Hydrocoral (Janaria mirabilis), mutualist species, Angel de la Guarda Island Protected Area, Gulf of California (Sea of Cortez), Mexico, Jul...

Robert Thompson / Common hermit crab (Pagurus bernhardus) in rock pool, Ballywhoriskey Point, County Donegal, Northern Ireland.

Sue Daly / Hermit crab (Pagurus prideaux) and Cloak anemone (Adamsia carciniopados), Trondheimsfjord, Norway, July.

Sue Daly / Hermit crab (Pagurus bernhardus), Jersey, British Channel Islands, June.

Constantinos Petrinos / Anemone hermit crab (Dardanus pedunculatus) on mooring line carrying sea anemones. Lembeh Strait, North Sulawesi, Indonesia.

Constantinos Petrinos / Anemone hermit crab (Dardanus pedunculatus) on mooring line carrying sea anemones. Lembeh Strait, North Sulawesi, Indonesia

Constantinos Petrinos / Spotted hermit crab (Dardanus megistos) running at night and stirring up sand. Lembeh Strait, North Sulawesi, Indonesia.

Sue Daly / Anemone hermit crab (Pagurus prideaux) attacking another, with Cloak anemones (Adamsia palliata) covering both their shells, Sark, British Channel Islands, UK, October.

Sue Daly / Anemone hermit crab (Pagurus prideaux) sifting gravel on the seabed for food, with a Cloak anemone (Adamsia palliata) covering its shell, Sark, British Channel Islands, UK, October.

Sue Daly / Common hermit crab (Pagurus bernhardus), Sark, British Channel Islands, UK, June.

Sue Daly / Common hermit crab (Pagurus bernhardus) Sark, British Channel Islands, UK, June.

Sue Daly / Common hermit crab (Pagurus bernhardus), Sark, British Channel Islands, UK, June.

Sue Daly / Common hermit crab (Pagurus bernhardus) with a Parasitic anemone (Calliactis parasitica) in its shell, Sark, British Channel Islands, UK, June.

Alex Mustard / Morgan's coral hermit crab (Paguritta morgani) looks out from its hole, surrounded by an orange sponge with zooanthids. Arborek jetty, Arborek Island, Raja Ampat, West Papua, Indonesia. Dampier Strait...

SCOTLAND: The Big Picture / Hermit crab (Pagurus prideauxi) with Cloak anemone (Adamsia palliata) on shell, South Arran Marine Protected Area, Isle of Arran, Scotland, UK, August.

SCOTLAND: The Big Picture / Common hermit crab (Pagurus bernhardus) on maerl bed in no take zone, South Arran Marine Protected Area, Isle of Arran, Scotland, UK, August.

Georgette Douwma / Jeweled anemone hermit crab (Dardanus gemmatus). Lembeh Strait, North Sulawesi, Indonesia.

Solvin Zankl / Blood-red hermit crab (Pagurus edwardsi) around 4cm, Comau Fjord, Patagonia, Chile

Tony Wu / Anemone hermit crab (Dardanus pedunculatus) capturing and eating a mollusc, Lembeh Strait, North Sulawesi, Indonesia.

SCOTLAND: The Big Picture / Horse mussel (Modiolus modiolus) bed with brittle stars and crabs, Shetland, Scotland, UK, September.

SCOTLAND: The Big Picture / Hermit crabs (Pagurus bernhardus) in lost lobster pot / creel, Orkney, Scotland, UK, January.

Tony Wu / Paguritta coral hermit crabs (Paguritta sp) looking out from burrows in coral, Papua New Guinea

Franco Banfi / Hermit crab (Pagurus sp) Little Strytan dive site, Eyjafjordur nearby to Akureyri, northern Iceland, North Atlantic Ocean.

Pascal Kobeh / Coral hermit crab (Dardanus pedunculatus) with sea anemones on shell, Sulu Sea, Philippines

Pascal Kobeh / Coral hermit crab (Dardanus pedunculatus) with sea anemones on shell, Sulu Sea, Philippines

Georgette Douwma / Hermit crab (Dardanus pedunculatus) Lembeh Strait, North Sulawesi, Indonesia.

Georgette Douwma / White-spotted hermit crab (Dardanus megistos) Mabul, Malaysia.

Georgette Douwma / White spotted hermit crab (Dardanus megistos) Lembeh Strait, Sulawesi, Indonesia.

Ann & Steve Toon / Hermit crab (Pagurus bernhardus) emering from whelk, Boulmer, Northumberland, UK, April

Ann & Steve Toon / Hermit crab (Pagurus bernhardus), Boulmer, Northumberland, April

Juergen Freund / Hermit crab (Dardanus pedunculatus) with anemones, at Kimbe Bay, West New Britain, Papua New Guinea.

Aflo / Krausii / coral hermit crab (Paguritta vittata) in hole, Miyako, Okinawa, Japan, May.

Aflo / Krausii / coral hermit crab (Paguritta vittata) in hole, Miyako, Okinawa, Japan, May.

Aflo / Krausii / coral hermit crab (Paguritta vittata) in hole, Kume Island, Okinawa, Japan. December.

Christophe Courteau / Common Hermit crab (Pagurus bernhardus) Brittany, France, January.

Alex Hyde / Common Hermit Crab (Pagurus bernhardus) in Flat Periwincle shell (Littorina obtusata). Isle of Mull, Scotland, UK. June.

Pascal Kobeh / Orange / Pacific red hermit crab (Elassochirus gilli), Alaska, USA, Gulf of Alaska. Pacific ocean.

Pascal Kobeh / White spot hermit crab (Dardanus megistos) at night, Maldives. Indian Ocean.

Sue Daly / Common Hermit Crab (Pagurus bernhardus) Bouley Bay, Jersey, British Channel Islands.

Sue Daly / Common Hermit Crab (Pagurus bernhardus) Bouley Bay, Jersey, British Channel Islands.

Sue Daly / Common Hermit Crab (Pagurus bernhardus) Bouley Bay, Jersey, British Channel Islands.

Sue Daly / Anemone Hermit Crab (Pagurus prideaux) with Cloak Anemone (Adamsia palliata) and Parasitic Anemone (Calliactis parasitica) Bouley Bay, Jersey, British Channel Islands.

Sue Daly / Common Hermit Crab (Pagurus bernhardus) Bouley Bay, Jersey, British Channel Islands.

Sue Daly / Anemone Hermit Crab (Pagurus prideaux) with Cloak Anemone (Adamsia palliata) Bouley Bay, Jersey, British Channel Islands.

Alex Hyde / Common Hermit Crab (Pagurus bernhardus) in shell of Edible Periwinkle (Littorina littorea). This close up shows the compound eyes. Northumberland, UK. May.

Alex Hyde / Common Hermit Crab (Pagurus bernhardus) in shell of Edible Periwinkle (Littorina littorea). Photographed on a white background in mobile field studio. Northumberland, UK. May.

Alex Hyde / Common Hermit Crab (Pagurus bernhardus) in shell of Edible Periwinkle (Littorina littorea). Photographed on a white background in mobile field studio. Northumberland, UK. May.

Alex Mustard / Hermit crab (Dardanus calidus) with hermit crab anemone's (Calliactis parasitica) attached to its shell. This anemone lives exclusively on the shells of hermit crabs. Tavolara Marine Protected Area, O...

Alex Mustard / Maroon hermit crab / gold ring hermit crab (Pagurus hemphilli) climbs on a kelp leaf, covered in colonial seamatts. Browning Pass, Port Hardy, Vancouver Island, British Columbia, Canada. North East Pa...

MYN / Les Meade / Hairy Hermit Crab (Pagurus hirsutiusculus) Meadowdale Beach, Puget Sound, Snomish County, Washington, June, meetyourneighbours.net project

MYN / Sheri Mandel / Blueband hermit crab (Pagurus samuelis), Malibu, California, USA, February, meetyourneighbours.net project

D. Parer & E. Parer-Cook / Hermit Crab (Dardanus lagopodes), Indonesia

Franco Banfi / Hermit crab (Paguridae) Arctic circle Dive Center, White Sea, Karelia, northern Russia

Sue Daly / Anemone Hermit Crab (Pagurus prideauxi). Maseline harbour, Sark, British Channel Islands, October.

Sue Daly / Anemone Hermit Crab (Pagurus prideauxi). Maseline harbour, Sark, British Channel Islands, October.

Sue Daly / Anemone Hermit Crab (Pagurus prideaux) courtship behaviour. Maseline Harbour, Sark, British Channel Islands, September.

Sue Daly / Anemone Hermit Crab (Pagurus prideauxi) mating behaviour. Maseline Harbour, Sark, British Channel Islands, September.

Sue Daly / Anemone Hermit Crabs (Pagurus prideaux) engaging in courtship behaviour. Maseline Harbour, Sark, British Channel Islands, September.

Norbert Wu / Hermit Crab (Diogenidae), South Australia, Australia

Sue Daly / Hermit crab (Pagurus prideaux) with cloak Anemone (Adamsia carcinopados) Channel Islands, UK October

David Shale / Hermit crab with anemone. Collected from coral sea mount near Dragon vent field on SW Indian Ridge, Indian Ocean.

David Shale / Hermit crab with anemone. Collected from coral sea mount near Dragon vent field on SW Indian Ridge, Indian Ocean.

David Shale / Deepsea Hermit crab (Paguroidea) from coral seamount, SW Indian Ridge, Indian Ocean, December 2011

Alex Mustard / Bareye hermit crab (Dardanus fucosus) makes its home in a conch shell as it crawls over the sand, West Palm Beach, Gulf Stream, West Atlantic Ocean, Florida, USA.

Alex Mustard / Stareye hermit crab (Dardanus venosus) in a canyon on a coral reef, East End, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Solvin Zankl / Hermit crab (Paguroidea) emerging from shell, San Pietro Island, Sardinia, Italy, Mediterranean, July

Birgitte Wilms / Hermit Crab (Paguritta gracilipes) in hard coral, Solomon Islands

Juergen Freund / Anemone hermit crab (Dardanus pedunculatus) with anemone on its shell, walking on the sandy sea bed. Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Hermit crab walking over seabed leaving tracks in the sand, Misool, Raja Ampat, West Papua, Indonesia

Juergen Freund / Anemone hermit cab (Dardanus pedunculatus) with several anemones on its shell. Lembeh Strait, North Sulawesi, Indonesia.