Mark Taylor / Tabby kitten stretching with arched back

Mark Taylor / Fluffy black kitten, 9 weeks old, stretching with arched back.

Mark Taylor / Black kitten Buxie, 10 weeks old, in defensive witch's cat display with back arched and hair standing up

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

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

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

Mitsuaki Iwago / Domestic Cat (Felis catus) grey kitten in defensive posture with back arched and hair raised