Steve Downer / Slug (Species unknown) descending on slime rope from leaf. UK. June.

Ingo Arndt / Land snail / Brown-lipped snail (Cepaea nemoralis) crawling over a razor blade. The constantly produced mucus is a protection shield between the sole of the snail and the razor blade whilst the snail...

Ammonite / Close-up of a Yellow slug (Limax flavus) moving towards the camera leaving a slime trail and extending and retracting its eyestalk, footage taken using an endoscopic camera, Bristol, England, UK, Marc...

Ammonite / Earthworm (Lumbricus terrestris) moving through leaf litter, footage taken using an endoscopic camera in controlled conditions, Bristol, England, UK, June.

Ammonite / Close-up of a Yellow slug (Limax flavus) leaving a slime trail as it moves, footage taken using an endoscopic camera, Bristol, England, UK, March.

Martin Dohrn / Cardinal fish (Apogon sp) moments after it has mistakenly tried to eat an ostracod. The ostracod then releases glowing mucus that is so bright that it can be seen through the body of the fish. This gi...

Doug Perrine / Grey faced / White eyed moray eel {Siderea thyrsoidea} and Bleeker's parrotfish sleeping wrapped in mucus.

Doug Perrine / Sponge {Ectyoplasia ferox} covered with mucus containing eggs. Bahamas

Norbert Wu / Larvacean (Oikopleura labradorensis) house, primitive animal spins mucus web, Arctic

David Fleetham / Chameleon parrotfish (Scarus chameleon), portrait at night. Sleeping in a mucus bubble secreted from large glands in gill cavity to protect fish from parasites. Fiji.

Ingo Arndt / Leopard slug (Limax maximus) mating, hanging from a rope of mucus. These slugs are hermaphrodites and can be seen here transferring sperm to one another through their male organs, Switzerland

Ingo Arndt / Leopard slug (Limax maximus) climbing and eating at the same time a rope of mucus after mating. These slugs are hermaphrodites and can be seen here transferring sperm to one another through their male...

Ingo Arndt / Leopard slug (Limax maximus) climbing and eating at the same time a rope of mucus after mating. These slugs are hermaphrodites and can be seen here transferring sperm to one another through their male...

Ingo Arndt / Brown-lipped snail (Cepaea nemoralis) crawling over a razor blade. The constantly produced mucus is a protection shield between the sole of the snail and the razor blade. The snail remains unharmed, G...

Ingo Arndt / Land snail (Chondropomedes magnum elizabethae) hanging in cave, with closed shell entrance, from a rope of mucus. A behaviour mostly likely to deter, Cuba

Ingo Arndt / Land snail (Chondropomedes magnum elizabethae) hanging in cave, with closed shell entrance, from a rope of mucus. A behaviour mostly likely to deter, Cuba

Ingo Arndt / Leopard slug (Limax maximus) mating, hanging from a rope of mucus. These slugs are hermaphrodites and can be seen here transferring sperm to one another through their male organs.Switzerland. Sequence...

Ingo Arndt / Leopard slug (Limax maximus) mating, hanging from a rope of mucus. These slugs are hermaphrodites and can be seen here transferring sperm to one another through their male organs.Switzerland. Sequence...

Ingo Arndt / Leopard slug (Limax maximus) mating, hanging from a rope of mucus. These slugs are hermaphrodites and can be seen here transferring sperm to one another through their male organs.Switzerland. Sequence...

Steve Downer / Slug (Species unknown) descending on slime rope from leaf. UK. June.

Steve Downer / Slug (Species unknown) descending on slime rope from leaf. UK. June.

Ingo Arndt / Leopard slug (Limax maximus) mating, hanging from a rope of mucus. These slugs are hermaphrodites and can be seen here transferring sperm to one another through their male organs.Switzerland. Sequence...

Mark Carwardine / Southern elephant seal (Mirounga leonina) close up portrait of pup with snotty nose resting in shallow water, Gold Harbour, South Georgia, November

Ingo Arndt / Great Grey Slug (Limax maximus) pair mating while hanging from mucus string, Switzerland

Ingo Arndt / Brown Lipped Snail (Cepaea nemoralis) crawling over razor blade, protected by its mucus, Germany

Ingo Arndt / Land Snail (Chondropoma sp) hanging in cave from mucus string, Cuba

Ingo Arndt / Brown Lipped Snail (Cepaea nemoralis) crawling over razor blade, protected by its mucus, Germany

Staffan Widstrand / Svalbard reindeer (Rangifer tarandus platyrhynchus) shedding velvet, looking into the camera, looking surprised, Spitsbergen, Svalbard, Norway, September

Pascal Kobeh / Close-up of the head of Bullethead parrotfish (Chlorurus sordidus) sleeping at night in its mucus cocoon, Great Barrier Reef, Australia. Coral sea.

Ammonite / Earthworm (Lumbricus terrestris) secreting lubricating mucus before moving away from camera, footage taken using an endoscopic camera in controlled conditions, Bristol, England, UK, June.

Alex Hyde / Great Grey / Leopard Slug (Limax maximus) mating, hanging from a rope of mucus. These slugs are hermaphrodites, and can be seen here transferring sperm to one another through their male organs. Derby...

Alex Hyde / Great Grey / Leopard Slug (Limax maximus) mating, hanging from a rope of mucus. These slugs are hermaphrodites, and can be seen here transferring sperm to one another through their male organs. Photo...

Georgette Douwma / Vermetid worm snail (Serpulorbis imbricatus / adamsii) eating its mucus net. Raja Ampat, Indonesia

Georgette Douwma / Vermetid worm snail (Serpulorbis imbricatus / adamsii) eating its mucus net. Bunaken National Park, Indonesia.

Georgette Douwma / Vermetid worm snail (Serpulorbis imbricatus / adamsii) eating its mucus net. Bunaken National Park, Indonesia.

Nick Upton / Edible snail (Helix pomatia) attached to tree trunk with a dried mucus epiphragm to prevent desiccation, Germany

Jeff Rotman / Male Steepheaded parrotfish (Scarus gibbus) in its intial phase, sleeping in protective mucus membrane at night, Red Sea

Doug Perrine / Pacific steephead parrotfish {Scarus gibbus} sleeping in mucus cocoon at night, Kimbe Bay, Papua New Guinea

Luciano Candisani / Parrotfish (Sparisoma vetula) sleeps in mucus bubble for defense, Caribbean Sea, Bonaire Island, Netherlands Antilles

Jeff Rotman / Bluebarred Parrotfish (Scarus ghobban) sleeping in rock crevice protected by mucus membrane. Egypt, Red Sea.

David Shale / Vibilia sp. (Hyperiidea, Vibiliidae). This is a genus that isn't too easy, even with a specimen under the microscope! This might be V. jeangerardi Lucas, 1845. The genus contains about 17 species, som...

Konrad Wothe / New Zealand Glow-worm (Arachnocampa luminosa) the larval stage of a fly, captures prey with hanging sticky tendrils of mucus, Fox Glacier, New Zealand

Norbert Wu / Bleeker's Parrotfish (Scarus bleekeri) sleeps in mucus net for defense, beak adapted for crunching coral, Fiji

GEORGETTE DOUWMA / Bullethead parrotfish sleeping in cocoon of mucus at night {Scarus sordidus} coral reef, Red Sea

Heidi & Hans-Juergen Koch / Brown Lipped Snail (Cepaea nemoralis) crawling over razor blade, protected by its mucus, Berlin, Germany

Michael Pitts / Bleeker parrotfish {Chlorurus bleeker} sleeping in mucus membrane

Mike Wilkes / Great grey slug (Limax maximus) and its mucus trail, UK

Emanuele Biggi / Panther flying frog (Rhacophorus pardalis) female depositing eggs in nest made of protein rich mucus hanging from leaf, Kubah National Park, Sarawak, Borneo.

Emanuele Biggi / Panther flying frog (Rhacophorus pardalis) females depositing eggs in nest made of protein rich mucus hanging from leaf, Kubah National Park, Sarawak, Borneo.

Tony Wu / Sea butterfly (Cavolinia uncinata),small pelagic mollusc, using nets of mucus to capture food. East China Sea, Kagoshima Prefecture, Japan.

Tony Wu / Sea butterfly (Cavolinia uncinata), small pelagic mollusc using nets of mucus to capture food. East China Sea, Kagoshima Prefecture, Japan.

David Fleetham / Palenose parrotfish (Scarus psittacus) terminal phase, sleeping at night in a mucus cocoon which it secretes as protection from predators, Hawaii, Pacific Ocean.

David Fleetham / Tricolor parrotfish (Scarus tricolor) supermale sleeping at night protected by a mucus cocoon that it secretes, with parasitic copepod caught in it, Tubbataha Reef, Philippines, Pacific Ocean.

Russell Laman / Reef manta (Mobula alfredi) getting cleaned of parasites, dead skin, bacteria, and mucus by Blacklip butterflyfish (Chaetodon kleinii) and Moon wrasse (Thalassoma lunare) at a cleaning station in Raja...

Nick Upton / Millipede (Leptoiulus sp.) feeding on the mucus of a Garden snail (Cornu aspersum) in a flowerpot at night, Wiltshire, UK, October.

David Fleetham / Bleeker's Parrotfish (Chlorurus bleekeri), surrounded by mucus bubble, on sea bed in reef at night, South Pacific, Fiji.

Pascal Kobeh / Bullethead parrotfish (Chlorurus sordidus) sleeping at night in its mucus cocoon, Red Sea, Egypt.

Nick Upton / European eel (Anguilla anguilla) migratory adult 'silver eel'trapped on a rock ledge on a sandy beach on a very low tide, Dunraven Bay, Glamorgan, Wales UK, September. Protected by their mucus...

Nick Upton / European eel (Anguilla anguilla) migratory adult 'silver eel'trapped in and partially emerged from a tide pool on a sandy beach on a very low tide, Dunraven Bay, Glamorgan, Wales UK, September...

Alex Mustard / Redlip parrotfish (Scarus rubroviolaceus) sleeps in a coral reef at night. Parrotfish sometimes make mucus cocoons to enclose their body while they sleep, but not always, as here. Misool, Raja Ampat,...