Alan Murphy/ BIA / Greater Roadrunner (Geococcyx californianus) hunting Western Diamondback Rattlesnake (Crotalus atrox), Arizona

Alan Murphy/ BIA / Greater Roadrunner (Geococcyx californianus) hunting Western Diamondback Rattlesnake (Crotalus atrox), Arizona

Ingo Arndt / Prairie Rattlesnake (Crotalus viridis viridis) in defensive posture, South Dakota

Michael & Patricia Fogden / Black-tailed Rattlesnake (Crotalus molossus) portrait, Chiricahua Mountains, Arizona

Pete Oxford / Eastern Diamondback Rattlesnake (Crotalus adamanteus), Little St. Simon's Island, Georgia

ZSSD / Colorado Desert Sidewinder (Crotalus cerastes laterorepens) on sand, venomous species native to deserts of California and Mexico

Jim Brandenburg / Western Rattlesnake (Crotalus viridis) in defensive posture, South Dakota

Jim Brandenburg / Western Rattlesnake (Crotalus viridis) in defensive posture, South Dakota

Larry Minden / Red Rattlesnake (Crotalus ruber) coiled on ground, Baja California, Mexico

Larry Minden / Red Rattlesnake (Crotalus ruber) with tongue extended, Baja California, Mexico

Jeff Foott / Mexican flag against blue sky. Coat of arms on flag depicting a Golden eagle (Aquila chrysaetos) feeding on Rattlesnake (Crotalus sp) whilst perched on a Prickly pear cactus (Opuntia sp), Oak (Quercus...

Karine Aigner / Western diamondback rattlesnake (Crotalus atrox) coiled up at base of Prickly pear cactus (Opuntia sp). Texas, USA. April.

Chris Mattison / Rattle from tail of rattlesnake (Crotalus sp) Arizona, USA

Chris Mattison / Rattles from tails of two Rattlesnakes (Crotalus sp) from an old (top) and young snake, Arizona, USA.

Lynn M Stone / Mojave Rattlesnake (Crotalus scutulatus) by Barrel Cactus (Freocactus sp.) in Sonoran Desert, Mesa, Arizona, USA. Non exclusive

Lynn M Stone / Mojave Rattlesnake (Crotalus scutulatus) by Barrel Cactus (Freocactus sp.) in Sonoran Desert, Mesa, Arizona, USA

Visuals Unlimited / California Kingsnake (Lampropeltis getula californiae) eating a Rattlesnake (Crotalus) after constricting it, California, USA

Visuals Unlimited / California Kingsnake (Lampropeltis getula californiae) eating a Rattlesnake (Crotalus) after constricting it to death, California, USA

Visuals Unlimited / California Kingsnake (Lampropeltis getula californiae) eating a Rattlesnake (Crotalus), California, USA

Visuals Unlimited / California Kingsnake (Lampropeltis getula californiae) eating a Rattlesnake (Crotalus), California, USA.

Daniel Heuclin / Panamint Rattlesnake (Crotalus stephensi) close up of scales, Death Valley National Park, California, USA, controlled conditions

Daniel Heuclin / Panamint rattlesnake (Crotalus mitchelli stephensi) close-up of rattling tail, Panamint mountains, Death valley NP, California, USA. Controlled conditions.

Daniel Heuclin / Panamint rattlesnake (Crotalus mitchelli stephensi) rattling tail, Panamint mountains, Death valley NP, California, USA. Controlled conditions.

Luciano Candisani / Western Diamondback Rattlesnake (Crotalus atrox) moving through habitat,

Albert Lleal / Western Diamondback Rattlesnake (Crotalus atrox) SEM close-up of keeled scales on the head at 14x magnification

Albert Lleal / Western Diamondback Rattlesnake (Crotalus atrox) albino, native to North America

Donald M. Jones / Western Rattlesnake (Crotalus viridis) in defensive posture, Montana

Donald M. Jones / Western Rattlesnake (Crotalus viridis) in defensive posture, Montana

Donald M. Jones / Western Rattlesnake (Crotalus viridis) in defensive posture, Montana

Jeff Foott / Pacific Rattlesnake (Crotalus oreganus) in defensive posture, Carrizo Plain National Monument, California

Donald M. Jones / Western Rattlesnake (Crotalus viridis) flicking tongue, Montana

Donald M. Jones / Western Rattlesnake (Crotalus viridis) in defensive posture, North America

Patricio Robles Gil / Rattlesnake (Crotalus sp) in defensive posture, Sierra del Carmen region, Mexico

Patricio Robles Gil / Rattlesnake (Crotalus sp) in defensive posture, Sierra del Carmen region, Mexico

Patricio Robles Gil / Sidewinder (Crotalus cerastes) rattlesnake moving across sand dunes at sunset, El Pinacate/Gran Desierto de Altar Biosphere Reserve, Sonora, Mexico

Patricio Robles Gil / Sidewinder (Crotalus cerastes) rattlesnake moving across sand dunes, El Pinacate/Gran Desierto de Altar Biosphere Reserve, Sonora, Mexico

Alan Murphy/ BIA / Greater Roadrunner (Geococcyx californianus) predating Western Diamondback Rattlesnake (Crotalus atrox) juvenile, Arizona

Alan Murphy/ BIA / Greater Roadrunner (Geococcyx californianus) predating Western Diamondback Rattlesnake (Crotalus atrox) juvenile, Arizona

Alan Murphy/ BIA / Greater Roadrunner (Geococcyx californianus) predating Western Diamondback Rattlesnake (Crotalus atrox) juvenile, Arizona

Alan Murphy/ BIA / Greater Roadrunner (Geococcyx californianus) predating Western Diamondback Rattlesnake (Crotalus atrox) juvenile, Arizona

Thomas Marent / Aruba Rattlesnake (Crotalus durissus) fangs, native to South America

Mark Carwardine / Santa Catalina Rattlesnake (Crotalus catalinensis) flicking tongue, Santa Catalina Island, Baja California, Mexico

Mark Carwardine / Santa Catalina Rattlesnake (Crotalus catalinensis), Santa Catalina Island, Baja California, Mexico

Mark Carwardine / Santa Catalina Rattlesnake (Crotalus catalinensis), Santa Catalina Island, Baja California, Mexico

Mark Carwardine / Santa Catalina Rattlesnake (Crotalus catalinensis) rattleless tail, Santa Catalina Island, Baja California, Mexico

Ingo Arndt / Prairie Rattlesnake (Crotalus viridis viridis) in defensive posture, South Dakota

Donald M. Jones / Western Rattlesnake (Crotalus viridis) rattling tail, western Montana

Donald M. Jones / Western Rattlesnake (Crotalus viridis) in defensive posture, western Montana