Jack Dykinga / Twisted and emerging limbs of Saguaro cacti (Carnegiea gigantea) Sonoran Desert near Tucson, Arizona, USA

Rolf Nussbaumer / Northern mockingbird (Mimus polyglottos) adult fighting with Golden-fronted Woodpecker (Melanerpes aurifrons) female over Texas Prickly Pear Cactus (Opuntia lindheimeri) Dinero, Lake Corpus Christi, S...

John Abbott / Giant prickly pear cactus (Opuntia echios var. gigantea) amongst carpetweed, Plazas Island, Galapagos

Rolf Nussbaumer / Eastern Cottontail (Sylvilagus floridanus) adult. Laredo, Webb County, South Texas, USA, April.

Rolf Nussbaumer / Golden-fronted Woodpecker (Melanerpes aurifrons), male perched on Texas Prickly Pear Cactus (Opuntia engelmanni). Laredo, Webb County, South Texas, USA, April.

Floris van Breugel / Cholla cactus (Opuntia) backlit by setting sun, Anza Borrego State Park. California, USA. April 2009.

Rolf Nussbaumer / Texas horse crippler cactus (Echinocactus texensis) in flower, Coastal Bend, Texas Coast, USA

Rolf Nussbaumer / Blue-throated Hummingbird (Lampornis clemenciae) male feeding on flowering Claret Cup Cactus (Echinocereus triglochidiatus) Chisos Basin, Chisos Mountains, Big Bend National Park, Chihuahuan Desert, W...

Rob Tilley / Agave close up abstract (Agave sp) Botanical Garden, San Miguel de Allende, Mexico

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

Stephen Dalton / Gulf Fritillary Butterfly (Agraulis vanillae) flying near cactus. Everglades, Florida, USA

Patricio Robles Gil / Barrel cactus (Ferocactus pilosus) Chihuahuan desert, Mexico

Anup Shah / Verreaux's sifaka (Propithecus verreauxi) 'hopping' across open ground to reach new feeding area, Berenty Private Reserve, Madagascar, October

Jack Dykinga / Penstemon (Penstemon sp) in flower against Saguaro cactus (Carnegiea gigantea) Finger Rock Canyon, Santa Catalina Mountains, Arizona, USA

Jack Dykinga / Saguaro cacti (Carnegiea gigantea) at sunset in the foothills of the Santa Catalina Mountains, near the Sutherland Wash, Catalina State Park, Arizona, USA

Jack Dykinga / Close-up of spines of the trunk of a Saguaro cactus (Carnegiea gigantea) Caboza Prieta National Wildlife Refuge, Arizona, USA

Jack Dykinga / Cacti in snow with fog at sunrise, Saguaro National Park, Arizona, USA

Jack Dykinga / Rainbow at sunset over desert hillside with Saguaro cacti, Table Mountain in the distance, Pusch Ridge Wilderness, Coronado National Forest, Santa Catalina Mountains, Arizona, USA

Jack Dykinga / Saguaro cacti (Carnegiea gigantea) Sand Tank Mountains, Barry M. Goldwater Range, Arizona, USA

Jack Dykinga / Saguaro cactus (Carnegia gigantea) lit up at night with star trails, Cabeza Prieta National Wildlife Refuge, Arizona, USA

Jack Dykinga / California poppies (Eschscholzia californica) flowering between the "ribs" of a dead Saguaro cactus (Carnegiea gigantea) Barry M. Goldwater Range, Arizona, USA

Jack Dykinga / Saguaro cactus (Carnegiea gigantea) twisted by exposure to frost, Maricopa Mountains Wilderness, Sonoran Desert National Monument, Arizona, USA

Jack Dykinga / Saguaro cacti (Carnegiea gigantea) silhouetted at sunrise, Sand Tank Mountains, Sonoran Desert National Monument, Arizona, USA

Jack Dykinga / Close up of Saguaro cactus (Carnegiea gigantea) and Teddybear cholla (Cylindropuntia bigelovii) in evening light, Tucson Mountain Park, Arizona, USA

Anup Shah / Ring-tailed Lemur (Lemur catta) female with infant (less than one month) riding on her back. Berenty Private Reserve, Madagascar. Oct 2008.

Inaki Relanzon / Ring-tailed lemur (Lemur catta) looking down from large spiney plant, Itampolo, South Madagascar

Jack Dykinga / Rainbow over Table Mountain and the Pusch Ridge Wilderness in the Santa Catalina Mountains, Arizona

Jack Dykinga / Close-up of two Barrel cacti (Ferocactus acanthodes) in the eastern Chihuahuan Desert, Mexico

Jack Dykinga / Dense stands of Prickly pear cactus (Opuntia sp) in Tamaulipas, Mexico

Jack Dykinga / A cluster of flowering Barrel cacti (Ferocactus stainsii) with Yuccas (Yucca sp) in the Eastern extension of the Chihuahuan Desert, Tamaulipas, Mexico

Jack Dykinga / Close-up of the twisted limbs of a freeze-damaged Saguaro Cactus (Carnegiea gigantea), with new limbs emerging. Sonoran Desert National Monument, Arizona

Rolf Nussbaumer / Daring Jumping Spider {Phidippus audax} adult on fruit of Texas Prickly Pear Cactus (Opuntia lindheimeri) Rio Grande Valley, Texas, USA, June

Jack Dykinga / Saguaro Cacti (Carnegiea gigantea) in a summer storm at sunset, with a rainbow in the background, Maricopa Mountains, Sonoran Desert National Monument, Arizona, USA

Jack Dykinga / Saguaro Cactus (Carnegiea gigantea) with new flowers emerging at the tip of its limb, Tucson Mountains, Saguaro NP, Arizona, USA

Jack Dykinga / Galloping Cactus (Stenocereus gummosus) amid flowering Sand Verbena (Abronia villosa) and Rock Daisies (Perityle emoryi), Vizcaino Desert, Baja California Sur, Mexico, Central America

Jack Dykinga / Sunset at Javalina Mountain and the Sand Tank Mountains, Sonoran Desert National Monument, Arizona, USA

Jack Dykinga / Saguaro Cactus (Carnegiea gigantea) at dawn with new flowers emerging at the tip of its limb, Saguaro NP, Arizona, USA

Jack Dykinga / Saguaro Cacti (Carnegiea gigantea) at sunrise, Sonoran Desert National Monument, Arizona, USA

Jack Dykinga / Saguaro Cacti (Carnegiea gigantea) silhouetted against the sunset in the Silver Bell Mountains, Saguaro NP, Arizona, USA

Jack Dykinga / Cardon Cacti (Pachycereus pringlei) on the shore of the Pacific Ocean at sunset, Baja California Sur, Mexico, Central America

Jack Dykinga / Night sky with trails of stars rotating around the North Star with a Saguaro Cactus (Carnegiea gigantea) silhouetted in the foreground, Cabeza Prieta NW Refuge, Arizona, USA

Jack Dykinga / Arizona Barrel Cactus (Ferocactus wislizenii) flower in full bloom amid the cactus spines, Saguaro NP, Arizona, USA

Jack Dykinga / Signal Hill petroglyphs at sunset with Saguaro Cacti (Carnegiea gigantea) and Tucson Mountains in the background, Saguaro National Monument, Arizona, USA

Jack Dykinga / Saguaro Cacti (Carnegiea gigantea) with detail of the cactus spines, Tucson Mountains, Saguaro NP, Arizona, USA

Jack Dykinga / Senita Cactus (Lophocereus crystallinum) amid Sand Verbena (Abronia villosa) and flowering Ice Plants (Mesembryanthemum crystallinum), Vizcaino Desert, Baja California Sur, Mexico, Central America

Jack Dykinga / Cardon Cactus (Pachycereus pringlei) and Galloping Cactus (Machaerocereus gummosus) amongst flowering Evening Primrose (Oenthera sp), Vizcaino Desert, Baja California Sur, Mexico, Central America

Jack Dykinga / Cardon Cactus (Pachycereus pringlei) reddened on the sun exposed side, Baja California Sur, Mexico, Central America

Jack Dykinga / Organ Pipe Cactus (Stenocereus thurberi) amongst flowering Brittlebush (Encelia farinosa) and Teddy Bear Cholla (Opuntia bigelovii), with the Ajo Mountains in the background Organ Pipe Cactus National...

Jack Dykinga / Saguaro Cactus (Carnegiea gigantea) with new arm emerging from its trunk, Cabeza Prieta NW Refuge, Arizona, USA

Jack Dykinga / Cardon Cactus (Pachycereus pringlei) reddened on the sun exposed side, Baja California Sur, Mexico, Central America

Jack Dykinga / Saguaro Cacti (Carnegiea gigantea) at sunrise, Cabeza Prieta NW Refuge, Sonoran Desert, Arizona, USA

Jack Dykinga / Teddy Bear Cholla (Opuntia bigelovii) and Saguaro Cacti (Carnegiea gigantea) lit by the afternoon light in the Sand Tank Mountains, Sonoran Desert National Monument, Arizona, USA

Jack Dykinga / Tangled Fishhook Cactus (Mammillaria microcarpa) in full flower after the summer rains, Saguaro NP, Arizona, USA

Jack Dykinga / Sand Verbena (Abronia villosa) and Evening Primrose (Oenothera sp) flowering beneath a Galloping Cactus (Stenocereus gummosus) Vizcaino Desert, Baja California Sur, Mexico, Central America

Jack Dykinga / Clusters of Barrel Cacti (Ferocactus stainesii) and Yuccas (Yucca sp) with the Sierra Madre in the background, Chihuahuan Desert, Mexico, Central America

Jack Dykinga / Organpipe Cactus (Cereus thurberi) rooted in volcanic rock on the coast of the Sea of Cortez at dawn, Baja California Sur, Mexico, Central America

Jack Dykinga / Cactus (Acanthocereus tetragonus) amid flowering Flaveria (Flaveria anomala) and Pink Floss Plant (Ageratum sp), Laguna Madre, Mexico, Central America

Jack Dykinga / California Poppies (Eschscholtzia californica) and flowering Spurge (Euphorbia sp) with a Cholla Cactus (Opuntia cholla) skeleton, Tres Virgenes, Baja California Sur, Mexico, Central America

Rolf Nussbaumer / Northern Raccoon {Procyon lotor} at water at night, Hill Country, Texas, USA

Rolf Nussbaumer / Lace Cactus {Echinocereus reichenbachii} flower abstract, Texas, USA

Jack Dykinga / Cane cholla cactus {Opuntia versicolor}, Lupins {Lupinus sparsiflorus} and Californian poppies {Exchscholtzia californica} flowering on Quinlan mountains, Tohono O'oodham Reserve, Arizona, USA

Jack Dykinga / Teddy bear cholla cactus {Opuntia bigelovii} growing on volcanic lava flow, Pinacate and Gran Desierto Altar Biosphere Reserve, Sonoran desert, Mexico

Jack Dykinga / Teddy bear cholla cactus {Opuntia bigelovii}, Brittlebush {Encelia farinosa} and Red owl's clover {Orthocarpus purpurascens} flowering on Harcuvar mountains, Arizona, USA with Arrastra mountains in th...

John Cancalosi / Harris antelope squirrel (Ammospermophilus harrisii) on cactus, Sonoran Desert, Arizona, USA

David Welling / Texas tortoise {Gopherus berlandieri} Texas, USA

John Cancalosi / Harris antelope squirrel (Ammospermophilus harrisii) on cactus, Sonoran Desert, Arizona

John Cancalosi / Harris' antelope squirrel (Ammospermophilus harrisii) Sonoran Desert, Arizona

Rolf Nussbaumer / Cereus greggii flower, Texas, USA.

Rolf Nussbaumer / Gilded flicker, male on saguaro cactus {Colaptes chrysoides} Arizona, USA

Rolf Nussbaumer / Saguaro cactus silhouette at sunset, Saguaro NP, Arizona, USA

Rolf Nussbaumer / Big Bend NP, Chisos mountains, Texas, . {Ocotillo sp}

Rolf Nussbaumer / Moon rising over Saguaro cactus, Saguaro NP, Arizona, USA

Rolf Nussbaumer / Big Bend NP, Chihuahuan desert, Texas, USA. Strawberry cactus + Prickly pear cactus.

Rolf Nussbaumer / Saguaro NP, Arizona, with Saguaro cactus + Silver cholla.

Juergen Freund / Cardon cactus silhouetted at sunset with moon, Baja California, Mexico

Pete Oxford / Ring-tailed lemur {Lemur catta} feeding at cactus flower Madagascar, Berenty

Pete Oxford / Large cactus ground finch {Geospiza conirostris} Tower (Genovesa) Is, Galapagos, tool making Book page 88

John Cancalosi / Harris' antelope squirrel (Ammospermophilus harrisii) Sitting on cactus & eating USA Arizona, Sonoran Desert.

NEIL NIGHTINGALE / Filming saguaro cactus flowers Arizona, USA

Kerstin Hinze / Fishhook Cactus (Mamillaria parkinsonii). Northern Mexico.

Mark Carwardine / Ring-tailed lemur {Lemur catta} feeding on cactus, Berenty Private Reserve, southern Madagascar

Mark Carwardine / Ring-tailed lemur {Lemur catta} feeding on cactus, Berenty Private Reserve, southern Madagascar

Mark Carwardine / Ring-tailed lemur {Lemur catta} mother and baby with cactus, Berenty Private Reserve, southern Madagascar

Mark Carwardine / Ring-tailed lemur {Lemur catta} feeding on cactus, Berenty Private Reserve, southern Madagascar

Floris van Breugel / Beavertail cacti (Opuntia basilaris) in bloom with California fan palm trees (Washingtonia filifera) behind, Anza-Borrego State Park, California, April.

Floris van Breugel / Hedgehog Cactus (Echinocereus) and an Ocotillo (Fouguieria splendens) in the distance with clouds above, Anza Borrego State Park desert, California, USA, April.

Floris van Breugel / Teddybear Cholla cacti (Cylindropuntia bigelovii) at sunset under a clearing storm over Anza Borrego State Park desert, California, USA, April.

Tui De Roy / Blue-footed booby (Sula nebouxii) and Land iguana (Conolophus sp.) with cacti. Espanola, Galapagos, June.

Tui De Roy / Cactus finch (Geospiza scandens) making a hole in cactus to extract moisture. Academy Bay, Santa Cruz Island, Galapagos Islands, Ecuador, December.

Tui De Roy / Cactus finch (Geospiza scandens) among trees. Academy Bay, Santa Cruz Island, Galapagos Islands, Ecuador, December.

Tui De Roy / Cactus finch (Geospiza scandens) Academy Bay, Santa Cruz Island, Galapagos Islands, Ecuador, November.

Jack Dykinga / Jumping cholla cactus bud (Opuntia fulgida) with radiating spines, Catalina State Park, Santa Catalina Mountains, Arizona, USA

Jack Dykinga / Lines of Saguaro cacti (Carnegiea gigantea) at dawn with the snowy north face of the Santa Catalina Mountains dominated by Table Mountain near Tucson, Arizona, USA

Jack Dykinga / Saguaro cactus (Carnegiea gigantea) spine patterns with weathered 'skin' forming a bark-like surface, Catalina State Park, Santa Catalina Mountains, Arizona, USA

Jack Dykinga / Saguaro cactus (Carnegiea gigantea) close up of sharp needles, Arizona, USA

Jack Dykinga / Saguaro cactus (Carnegiea gigantea) small limb on large plant, Arizona, USA