Klaus Echle / Badger (Meles meles), back arched and fur on end, chases away Shropshire sheep. The Black Forest, Germany, May.

Bernard Castelein / Desert / Asiatic Wild Cat (Felis silvestris ornata) portrait standing, stretching with back arched, Rajasthan, India

Petra Wegner / Scottish Fold cat, tabby coated portrait, standing with back arched in defensive posture

Tim Laman / Arched roots of Red mangrove (Rhizophora mangle) cross over the spiked roots of a Mangrove apple tree (Sonneratia alba) Kostrae Island, Federated States of Micronesia.

Tim Laman / Arched roots of Red mangrove (Rhizophora mangle) cross over the spiked roots of a Mangrove apple tree (Sonneratia alba) which supports ferns and other epiphytes. Kostrae Island, Federated States of Mi...

Jane Burton / Red swordtail {Xiphophorus helleri} males sparring, swimming backwards at each other with bodies arched and tails displayed, females in the foreground, captive, from Central America

Steven Kazlowski / Arched iceberg floating off the western Antarctic peninsula, Southern Ocean

Steven Kazlowski / Arched iceberg floating off the western Antarctic peninsula, Southern Ocean

Steven Kazlowski / Arched iceberg floating off the western Antarctic peninsula, Southern Ocean

Jane Burton / Chocolate Labrador Retriever pup playing with chocolate Birman-cross kitten. Note the kitten's arched back and hairs standing on end in play posture.

Jane Burton / Black and white Domestic cat kitten {Felis catus} with back arched in aggression, UK

Jane Burton / Domestic Cat, ginger kitten with arched back in play posture, fur standing on end and staring at sibling