Cats are fascinating little creatures, from their nuanced vocalization styles down to their complex and diverse body language. The mystery of it all is almost maddening. If your cat is walking with an arch, that can indicate a range of emotions from pure pleasure to absolute fear.
If you're standing up and your cat is milling around by your feet with an arched contour to her back and body, her stance is probably a positive one, notes the Humane Society of the United States. She's probably hoping you'll kneel down and give her back some gentle strokes -- aww. If your cat's physique automatically goes into arch form at the mere sight of your hand, it's probably because she's happy to see you and craves some interaction and TLC.
A cat might be scared, mad or in full defense mode if he's arching his back in the stereotypical pose of a Halloween cat, according to the Humane Society of the United States.
Apart from the arch, notice your cat's hair. If it's bristling, then you probably have your answer. Your cat is very, very terrified or upset about something, such as a perceived or real predator, or an impending trip to the veterinarian's office -- the poor cutie.
The ASPCA states that a cat walking with an arch might be in a spirited and playful mood. If your cat is walking around stealthily with an arch to his back, perhaps he's just getting ready to quickly swoop into his playmate, whether it's another pet in your household or even you.
In some instances, a cat walking with an arch can be a sign of a medical problem. According to the Merck Manual for Pet Health, a cat who's simultaneously slightly hunched over while walking with an arch might have a painful bellyache. Other indications of stomach pain in felines are meowing and crying. So if you notice all of these things together, a veterinarian appointment could be in order. The culprit could be anything from a classic case of diarrhea to gastrointestinal parasites.