Alex Hyde / Indian moon / Indian luna Moth (Actias selene) close up of defensive spines on caterpillar. Captive.

Rod Williams / North American Porcupine (Erethizon dorsatum). Captive. Endemic to North America. Captive. UK, May.

Georgette Douwma / Black-blotched Porcupinefish / Short-spine Porcupinefish (Diodon liturosus) and a Klein's butterflyfish (Chaetodon kleinii) sheltering in barrel sponge. Komodo National Park, Indonesia.

Steve Nicholls / Skeleton of a Python (Python sp)

Juergen Freund / Spine-cheek anemonefish (Premnas biaculeatus) with baby amongst anemone tentacles, Bali, Indonesia, Indo-pacific.

Alex Hyde / Yellow streaked tenrec {Hemicentetes semispinosum} at night with spines erected in threat display, Maroansetra, Madagascar

Alex Hyde / Grey caterpillar covered in defensive spines, photographed on a white background. Maroantsetra, Northeast Madagascar

Mark Carwardine / Blue whale (Balaenoptera musculus) surfacing, showing blowhole and vertebrae of spine, Endangered species, Sea of Cortez, Baja California, Mexico

Stephen Dalton / Mud dauber wasp (Sceliphron caementarium) flying over cactus spines, Everglades NP, Florida, USA

Paul Hobson / Hedgehog (Erinaceus europaeus) released adult in garden at night, with house in background, Peak District, England, UK

Claudio Contreras / Balloon fish (Diodon holocanthus) with defensive spines, Puerto Morelos National Park, Caribbean Sea, Mexico, January

Juergen Freund / Spine cheeked anemonefish (Premnas biaculeatus). Indo-pacific

Piotr Naskrecki / Spiked Spider (Gasteracantha sp) their abdomen, or opisthosoma, is heavily sclerotized and armed with hard spines possibly to protect against birds and lizards, Solomon Islands

Tim Fitzharris / Common Porcupine (Erethizon dorsatum) portrait, Montana

Gerry Ellis / Common Porcupine (Erethizon dorsatum) climbing tree, North America

Gerry Ellis / African Hedgehog (Atelerix algirus) portrait, northwest Africa

Michael & Patricia Fogden / Boyd's Forest Dragon (Hypsilurus boydii) portrait, Queensland, Australia

Tim Fitzharris / Common Porcupine (Erethizon dorsatum) feeding on fruit, Montana

Matthias Breiter / Common Porcupine (Erethizon dorsatum) in willow tree near the Denali highway, Alaska

Flip Nicklin / Long-spine Porcupinefish (Diodon holocanthus) in defense posture, North America

Michael Quinton / Common Porcupine (Erethizon dorsatum) feeding on Pussy Willow (Salix discolor) in spring, Alaska

Michael Quinton / Common Porcupine (Erethizon dorsatum) sitting in a tree in winter, Yellowstone National Park, Wyoming

Michael Quinton / Common Porcupine (Erethizon dorsatum) feeding on Pussy Willow (Salix discolor) in spring, Alaska

Tui De Roy / Woodpecker Finch (Camarhynchus pallidus) using cactus spine to extract grub from dead wood, Santa Cruz Island, Galapagos Islands, Ecuador

Mitsuaki Iwago / Thorny Devil (Moloch horridus) on sand, Australia

Mark Moffett / Slug Caterpillar (Setora fletcheri) shows warning coloration and spines loaded with toxins that erect when the animal is disturbed, Tam Dao National Park, Vietnam

Fred Bavendam / California Sea Cucumber (Parastichopus californicus) underwater, Vancouver Island, British Columbia, Canada

Andy Sands / Privet hawkmoth (Sphinx ligustri) first instar larva resting along Privet leaf spine, UK, July, captive

Ingo Arndt / Saddleback Moth (Sibine horrida) caterpillar with poisonous spines, Costa Rica

Ingo Arndt / Crowned Frog (Anotheca spinosa) in cloud forest, Costa Rica

Ingo Arndt / Crowned Frog (Anotheca spinosa) in cloud forest, Costa Rica

MYN / Mac Stone / Small spine sea stars (Echinaster spinulosus) in various stages of growth, Florida, USA, September. meetyourneighbours.net project

Tui De Roy / Marine Iguana (Amblyrhynchus cristatus) dorsal spines, Galapagos Islands, Ecuador

Tui De Roy / Marine Iguana (Amblyrhynchus cristatus) dorsal spines, Galapagos Islands, Ecuador

Tui De Roy / Marine Iguana (Amblyrhynchus cristatus) dorsal spines, Galapagos Islands, Ecuador

Piotr Naskrecki / Greenhouse Camel Cricket (Diestrammena asynamora), Woburn, Massachusetts

Christian Ziegler / Cup Moth (Limacodidae) caterpillar has poisonous spines for protection, Barro Colorado Island, Panama

Norbert Wu / Cockscomb Nudibranch (Janolus barbarensis), Vancouver Island, British Columbia, Canada

Piotr Naskrecki / Cup Moth (Limacodidae) aposematically colored caterpillar with spines that can deliver an extremely painful sting, Atewa Range Forest Reserve, Ghana

Ole Jorgen Liodden / Polar Bear (Ursus maritimus) cub walking on whale spine. Spitsbergen, Svalbard, August.

Georgette Douwma / Spinecheek Anemonefish (Premnas biaculeatus) in host anemone in coral (Goniopora sp). Bunaken National Park, North Sulawesi, Indonesia.

Daniel Heuclin / Close up of spine attached to leg of cock used in Cock fighting, Philippines, February 2007

Pete Oxford / Long-spine Porcupinefish (Diodon holocanthus) in Stove Pipe Sponge (Aplysina archeri), Bonaire, Netherlands Antilles, Caribbean

Juergen Freund / Spinecheek anemonefish (Premnas biaculeatus) in bleached anemone host, Kimbe Bay, West New Britain, Papua New Guinea.

Birgitte Wilms / Spine-cheek Anemonefish (Premnas biaculeatus) in anemone, Solomon Islands

Yva Momatiuk & John Eastcott / Short-beaked Echidna (Tachyglossus aculeatus), Nambung National Park, Western Australia, Australia

Chien Lee / Nymphalid Butterfly (Cethosia sp) caterpillars with aposematic coloration, Kubah National Park, Malaysia

Chien Lee / Cup Moth (Limacodidae) caterpillar with bristles capable of inflicting painful stings, Kuching, Borneo, Malaysia

Pete Oxford / Small Painted Locust (Schistocerca literosa) on cactus spines, Puerto Ayora, Santa Cruz Island, Galapagos Islands, Ecuador

Pete Oxford / Small Painted Locust (Schistocerca literosa) on cactus, Puerto Ayora, Santa Cruz Island, Galapagos Islands, Ecuador

Luciano Candisani / Black River Stingray (Potamotrygon motoro) venomous spine located in the base of the elongated caudal tail, Rio Negro, Pantanal, Brazil

Mark Carwardine / Blue whale (Balaenoptera musculus) surfacing, Endangered species, Sea of Cortez, Baja California, Mexico

Mark Carwardine / Blue whale (Balaenoptera musculus) surfacing, showing blowhole and vertebrae of spine, Endangered species, Sea of Cortez, Baja California, Mexico

Mary McDonald / Marabou Stork (Leptoptilos crumeniferus) perched on the spine of a large mammal carcass, feeding on remains, Ndutu, Serengeti NP, Tanzania, East Africa.

Michel Roggo / Spinycheek crayfish (Orconectes limosus) Europe

Tim Laman / Humpback whale (Megaptera novaeangliae) dorsal spine, off Massachusetts, USA.

Jeff Rotman / Close up of dorsal fin of California hornshark (Heterodontus francisci) of with horn spine, Channel Islands, California (USA) Pacific Ocean.

Tui De Roy / Marine Iguana (Amblyrhynchus cristatus) spines, Galapagos Islands, Ecuador

Tui De Roy / Marine Iguana (Amblyrhynchus cristatus) spines, Galapagos Islands, Ecuador

Murray Cooper / Saturniid Moth (Saturniidae) caterpillar, Amazon, Ecuador

Murray Cooper / Tent Caterpillar Moth (Lasiocampidae) caterpillar, Amazon, Ecuador

Albert Lleal / Mediterranean Mantis (Iris oratoria) detail of spines on front legs at 14x magnification, Spain

Jeff Rotman / Spine-cheek Anemonefish (Premnas biaculeatus) amongst tentacles of Bubbletip anemone, Lembeh Strait, Celebes Sea, Sulawesi, Indonesia.

John Cancalosi / Fossilised fish

Fred Bavendam / Titan Triggerfish (Balistoides viridescens) with spines from a sea urchin it has eaten, Bali, Indonesia

Fred Bavendam / Common Lionfish (Pterois volitans), Nusa Tengarra, Indonesia

Fred Bavendam / Common Lionfish (Pterois volitans), Bali, Indonesia

Fred Bavendam / Common Lionfish (Pterois volitans), Bali, Indonesia

Fred Bavendam / Common Lionfish (Pterois volitans), Milne Bay, Papua New Guinea

Fred Bavendam / Spotfin Lionfish (Pterois antennata), Kimbe Bay, Papua New Guinea

Fred Bavendam / Shortfin Turkeyfish (Dendrochirus brachypterus), Lembeh Strait, Indonesia

Martin van Lokven / Green Iguana (Iguana iguana) foot, Selva Verde, Costa Rica

Fred Bavendam / Spine-cheek Anemonefish (Premnas biaculeatus) pair living with a Bulb Tentacle Sea Anemone (Entacmaea quadricolor), Bali, Indonesia

Fred Bavendam / Puget Sound King Crab (Lopholithodes mandtii), Vancouver Island, British Columbia, Canada

Fred Bavendam / Scorpionfish (Rhinopias sp), Milne Bay, Papua New Guinea

Chris Newbert / Fire Urchin (Asthenosoma varium) detail showing the colors and pattern of spines on its surface, Indonesia

GEORGETTE DOUWMA / Spinecheek anemonefish (Premnas biaculeatus) amongst tentacles of its exclusive host, the Bubble tip anemone (Entacmaea quadricolor) Raja Ampat, West Papua, Indonesia.

GEORGETTE DOUWMA / Spinecheek anemonefish (Premnas biaculeatus) amongst tentacles of its exclusive host, the Bubble tip anemone (Entacmaea quadricolor) Raja Ampat, West Papua, Indonesia.

Juergen Freund / Diver coaxes a Spine-cheek anemonefish (Premnas biaculeatus) to come out of its anemone, Indo-pacific

Piotr Naskrecki / Cup Moth (Limacodidae) caterpillar, Mamang River Forest Reserve, Ghana

Piotr Naskrecki / Cup Moth (Limacodidae) caterpillar, Ghana

Piotr Naskrecki / Cup Moth (Limacodidae) caterpillar with spines that can deliver an extremely painful sting, Virachey National Park, Cambodia

Pete Oxford / Long-spine Porcupinefish (Diodon holocanthus) uninflated on ocean floor, Isabella Island, Galapagos Islands, Ecuador

Michael & Patricia Fogden / Crowned Frog (Anotheca spinosa) male seeking shelter in bromeliad during rain storm, Costa Rica

Michael & Patricia Fogden / Crowned Frog (Anotheca spinosa) male, Costa Rica

Michael & Patricia Fogden / Crowned Frog (Anotheca spinosa) male, Costa Rica

GEORGETTE DOUWMA / Spine cheeked anemonefish (Premnas biaculeatus). Papua New Guinea

GEORGETTE DOUWMA / Spine cheeked anemonefish (Premnas biaculeatus) in anemone, Papua New Guinea

Doug Perrine / Spine cheeked anemonefish {Premnas biaculeatus} in Anemone {Entacmea quadricolor} Kimbe Bay, Papua New Guinea

Solvin Zankl / Three-Spine Cavoline {Diacria trispinosa} a deepsea sea butterfly, Atlantic ocean

Norbert Wu / Purple Sea Urchin (Strongylocentrotus purpuratus), Vancouver Island, British Columbia, Canada

Tim Laman / Spinecheek anemonefish (Premnas biaculeatus) small male and large female amongst anemone tentacles, Wakatobi Islands, Sulawesi, Indonesia.

Tim Laman / Spinecheek anemonefish (Premnas biaculeatus) small male and large female amongst anemone tentacles, Wakatobi Islands, Sulawesi, Indonesia.

Tim Laman / Spinecheek anemonefish (Premnas biaculeatus) male, Wakatobi Islands, Sulawesi, Indonesia.

Tim Laman / Spinecheek anemonefish (Premnas biaculeatus) male, Wakatobi Islands, Sulawesi, Indonesia. June

Scott Leslie / Atlantic Sea Raven (Hemitripterus americanus) baby, St. Margaret's Bay, Nova Scotia, Canada