Philippe Clement / Compass / Fishhook Barrel Cactus (Ferocactus wislizeni). Organ Pipe Cactus National Monument, Arizona, USA 2007

Philippe Clement / Chain fruit / Jumping cholla (Opuntia / Cylindropuntia fulgida) fruit. Organ Pipe Cactus National Monument, Arizona, USA

Philippe Clement / Ocotillo (Fouquieria splendens) flowers and thorns. Organ Pipe Cactus National Monument, Arizona, USA.

Philippe Clement / Artichoke thistle / Cardoon flower (Cynara cardunculus). Spain.

Philippe Clement / Artichoke thistle / Cardoon flower (Cynara cardunculus). Spain.

Philippe Clement / Pima pineapple cactus (Coryphantha robustispina). Organ Pipe Cactus National Monument, Arizona, USA

Philippe Clement / Parry's Century Plant (Agave parryi). Organ Pipe Cactus National Monument, Arizona, USA

Philippe Clement / Chain fruit / Jumping cholla (Opuntia / Cylindropuntia fulgida) fruit being removed from shoe of hiker. Organ Pipe Cactus National Monument, Arizona, USA

Philippe Clement / Pima pineapple cactus (Coryphantha robustispina), close-up of spines. Organ Pipe Cactus National Monument, Arizona, USA

Philippe Clement / Chain fruit / Jumping cholla (Opuntia / Cylindropuntia fulgida) fruit being removed from shoe of hiker. Organ Pipe Cactus National Monument, Arizona, USA

Philippe Clement / Parry's Century Plant (Agave parryi). Organ Pipe Cactus National Monument, Arizona, USA

Philippe Clement / Pima pineapple cactus (Coryphantha robustispina), close-up of spines. Organ Pipe Cactus National Monument, Arizona, USA

Philippe Clement / Chain fruit / Jumping cholla (Opuntia / Cylindropuntia fulgida) fruit being removed from shoe of hiker. Organ Pipe Cactus National Monument, Arizona, USA

Philippe Clement / Desert spiny lizard (Sceloporus magister) climbing Ocotillo (Fouquieria splendens). Saguaro National Park, Arizona, USA

Philippe Clement / Compass / Fishhook Barrel Cactus (Ferocactus wislizeni). Organ Pipe Cactus National Monument, Arizona, USA 2007

Philippe Clement / Chain fruit / Jumping cholla (Opuntia / Cylindropuntia fulgida) fruit. Organ Pipe Cactus National Monument, Arizona, USA

Philippe Clement / Pima Pineapple Cactus (Coryphantha robustispina). Organ Pipe Cactus National Monument, Arizona, USA

Philippe Clement / Chain fruit / Jumping cholla (Opuntia / Cylindropuntia fulgida) fruit. Organ Pipe Cactus National Monument, Arizona, USA

Philippe Clement / Pima pineapple cactus (Coryphantha robustispina). Organ Pipe Cactus National Monument, Arizona, USA

Philippe Clement / Chain fruit / Jumping cholla (Opuntia / Cylindropuntia fulgida) fruit. Organ Pipe Cactus National Monument, Arizona, USA

Philippe Clement / Artichoke thistle / Cardoon flower (Cynara cardunculus). Spain.

Philippe Clement / Artichoke thistle / Cardoon flower (Cynara cardunculus). Spain.

Philippe Clement / Cactus wren (Campylorhynchus brunneicapillus) perched on Chain fruit / Jumping cholla (Cylindropuntia fulgida). Organ Pipe Cactus National Monument, Arizona, USA

Philippe Clement / Buckhorn cholla (Opuntia acanthocarpa) in Saguaro National Park, Arizona, USA

Nick Garbutt / Wagler's / Temple pitviper (Tropidolaemus wagleri) on spiney stem. Bako National Park, Sarawak, Borneo

John Cancalosi / Male Northern cardinal {Cardinalis cardinalis} perching on Ocotilla cactus, Arizona, USA

WILLIAM OSBORN / Sea holly close-up of flowers {Eryngium maritimus} Mid Glamorgan, Wales, UK

Jabruson / Protective thorns on Kapok tree trunk {Ceiba pentandra} Odzala NP, DR Congo

Nick Garbutt / Octopus tree close-up {Didierea trolli} Spiny forest, S Madagascar

WILLIAM OSBORN / Sea holly on beach {Eryngium maritimus} Mid Glamorgan, Wales, UK

Juergen Freund / Diver with Crown of thorns starfish {Acanthaster planci} Indo-Pacific ocean

Nature Production / A swarm of treehoppers {Cyphonia sp} simulating thorns, Costa Rica

Jack Dykinga / Cottontop cactus (Echinocactus polycephalus) with dawn light, Goldwater Range, Arizona

Jack Dykinga / Skeleton of Teddy Bear Cholla (Opuntia bigelovii) and Saguaro Cacti (CArnegiea gigantea) at sunrise, Cabeza Prieta National Wildlife Refuge, Arizona

Jack Dykinga / Agave (Agave lophantha) on rock face with red flowering Bouvardia sp, Sierra Madre Oriental, Mexico

Jack Dykinga / Ocotillo (Fouquieria splendens) and Saguaro (Carnegiea gigantea) cacti silhouetted against a colourful sunset, Cabeza Prieta National Wildlife Reserve, Arizona

Jack Dykinga / Close-up of Agave (Agave montana) with red thorns / spines and interesting patternation on blades, Sierra Madre Oriental mountain range, Tamaulipas, Mexico

Jack Dykinga / Close-up of Agave (Agave montana) with red thorns / spines and interesting patternation on blades, Madrone and Oak trees in background, Sierra Madre Oriental mountain range, Tamaulipas, Mexico

Jack Dykinga / Agave (Agave americana protoamericana) in a forest of Oak trees, Sierra Madre Oriental mountain range, Mexico

Hanne & Jens Eriksen / Scrub warbler {Scotocerca inquieta buryi}, singing in thorn tree, Mahweet, Yemen, 24 Jan 2006

Hanne & Jens Eriksen / Menetries's warbler {Sylvia mystacea}in Acacia tree, adult male, Tihama, Yemen

Doug Wechsler / Reticulated planthoppers (Pterodictya reticularis) on Zanthoxylon, Ecuador

GEORGETTE DOUWMA / Table coral showing damage caused by Crown of Thorns starfish Red Sea Egypt

Constantinos Petrinos / Giant Triton trumpet shell (Charonia tritonis) natural predator of Crown of thorns starfish, Sulawesi, Indonesia

Pete Oxford / Thorn mimic treehopper (Membracidae) Cloud forest, Ecuador

Jack Dykinga / Hedgehog Cactus (Echinocereus engelmanni) with pink / purple flowers, Teddy Bear Chollas (Opuntia bigelovii) in the distance, Joshua Tree National Park, California

Dave Bevan / Wart Biter (Decticus verrucivorus) on thorny twig, Hungry

Philippe Clement / Gemsbok cucumber (Acanthosicyos naudinianus) Kalahari desert, Kgalagadi Transfrontier Park, South Africa

Philippe Clement / Close-up of Camelthorn tree {Vachellia erioloba} seed pods, thorns and leaves, Kgalagadi Transfrontier Park, South Africa

Philippe Clement / Milk Bonnet Fungus (Mycena galopus) growing on husk of Sweet chestnut (Castanea sativa) Belgium

Simon Colmer / Dwarf Gorse (Ulex minor) in flower, Steadham Common Nature Reserve, Sussex, UK

PREMAPHOTOS / Treehoppers (Enchonopa concolor) mimic thorns on a thorny Solanum sp. plant, Brazil

Rolf Nussbaumer / Black-throated Sparrow (Amphispiza bilineata) on Texas Prickly Pear Cactus (Opuntia lindheimeri), Starr County, Rio Grande Valley, Texas, USA. April 2002

Rolf Nussbaumer / Melodious Warbler (Hippolais polyglotta) on bramle, Scrivia River, Italy. May 1997

Rolf Nussbaumer / Female Hooded Warbler (Setophaga citrina) High Island, Texas, USA. April 2001

Rob Tilley / Close up of spines of Octopus Cactus {Stencereus alamosensis} Desert Botanical Museum, Phoenix, Arizona, USA

Rob Tilley / Ocotillo / Coachwhip / Jacob's Staff in flower (Fouquieria splendens) against the sky, Sonora Desert Museum, Tucson, Arizona, USA

David Kjaer / Male Stonechat (Saxicola rubicola) perched on Gorse (ulex europaeus), Wales UK

David Kjaer / Meadow Pipit (Anthus pratensis) perched on flowering Gorse (Ulex europaeus) Pembrokeshire UK

John Cancalosi / Prickly Pear cactus pad (Opuntia spp) in Sonoran Desert, Arizona, USA

Shattil & Rozinski / North american pika {Ochotona princeps} carrying thistle spike, USA

Philippe Clement / Golden thistle {Scolymus hispanicus} Spain

Doug Perrine / Crown of thorns starfish {Acanthaster planci} feeding on coral, Similan Is, Thailand

Pete Oxford / Stilt roots with thorns, Amazonian rainforest, Ecuador

Nick Garbutt / Close-up of thorns on Stemless asam paya palm {Eleiodoxa conferta} Swamp forest, Bako National Park, Sarawak, Borneo.

Pete Oxford / Thorn mimic treehoppers on trunk {Membracidae} Manu Cloud Forest, Peru

GEORGETTE DOUWMA / Crown of thorns starfish {Acanthaster planci} Red Sea, Egypt

Anup Shah / Nubian woodpecker {Campethera nubica} Serengeti NP, Tanzania

Willem Kolvoort / Cactus on the slopes of the Voltzberg / Voltz mountain, Central Surinam Nature Reserve, Surinam . 2003.

Nigel Bean / Variable wheatear {Oenanthe picata} Black-crowned race, Islamabad, Pakistan

Hermann Brehm / Ring-tailed lemur (Lemur catta) Berenty, Madagascar

Constantinos Petrinos / Dark Chanting Goshawk {Melierax metabates} Masai Mara, Kenya

Hanne & Jens Eriksen / Yellow spotted agama lizard {Trapelus flavimaculatus}, Jiddat Al Harasis, Oman

Tom Vezo / Vermilion Flycatcher {Pyrocephalus rubinus} Arizona, USA.

Tom Vezo / Cactus Wren {Campylorhychus brunneicapillus} perching on cactus, Arizona, USA.

Hanne & Jens Eriksen / Fork tailed Drongo {Dicrurus adsimilis} perching in bush, Kruger NP, South Africa.

Hanne & Jens Eriksen / Stout cisticola {Cisticola robustus} perching on Acacia branch, Nairobi NP, Kenya.

GEORGETTE DOUWMA / Close-up of thorns on stem of Dog rose {Rosa canina} UK.

GEORGETTE DOUWMA / Thorns on stem of Dog rose {Rosa canina} UK.

GEORGETTE DOUWMA / Close-up of thorns on stem of Dog rose {Rosa canina} UK.

Tony Heald / Brant's whisling rat {Paratomys brantsii} Kgalagadi Transfrontier Park, South Africa

David Kjaer / Brown towhee {Pyrgisoma fuscum} Arizona, USA

Constantinos Petrinos / Dark Chanting Goshawk {Melierix metabates} on thorny branch, Masai Mara, Kenya.

Peter Blackwell / White throated bee eater {Merops albicollis} Samburu NR, Kenya

Bernard Castelein / White-browed coucal {Centropus superciliosus} Lake Nakuru, Kenya

Doug Perrine / Scalefin anthias ready to shelter in Crown of Thorns starfish, Papua New Guinea

Philippe Clement / Close-up of Agave thorns {Agave salmiana}, Botanical gardens, Belgium.

Kim Taylor / Thorny Devil (Moloch horridus). Northern Australia.

Luiz Claudio Marigo / Flowering tree euphorbia {Euphorbia nyikae} Buffalo Springs NR, Kenya

Fabio Liverani / {Azteca sp} ants on Acacia, Santa Rosa NP, Guanacaste, Costa Rica

GEORGETTE DOUWMA / Crown-of-Thorns starfish (Acanthaster planci) feeds on coral, Irian Jaya / West Papua, Indonesia (West Papua).

Tony Heald / Kirk's / Damara dik-dik {Madoqua kirki} male browsing, Etosha NP, Namibia

Richard Du Toit / White crowned shrike {Eurocephalus anguitimens} Etosha NP, Namibia

GEORGETTE DOUWMA / Crown of thorns starfish {Acanthaster planci} Red Sea

Pete Oxford / Caatinga vegetation, thorns #NAME? storage, Bahia state, Brazil

Pete Oxford / Cholla cactus flower {Opuntia sp} California, USA.