Many Pain Receptors

• Like humans, cats have pain receptors in their skin, the covering of bones, on the surfaces of joints, the tissues lining the chest and abdomen, the cornea and tissues around the eyes and the meninges of the brain and spinal cord.
  
  

Why Cats Hide Pain

• Unlike dogs, who receive support from their pack, instinct tells cats they must rely on themselves for safety and survival. To a cat's way of thinking, showing any sign of weakness would make it vulnerable to rivals and predators, so it functions normally despite pain.
  
  

Hiding and Hissing

• Hiding, hissing, growling and lashing out or aggression are all ways cats react to pain. Cats that are in so much pain they can't defend themselves hide to stay out of harm's way. An injured cat hisses and growls or becomes aggressive to ward off the threat of further injury.
  
  

Painful Body Language

• Cats in pain often sit or rest in a crouched position. Some react to pain by trembling or shaking. And cats whose eyes hurt often keep their eyes closed.
  
  

Other Reactions

• Other reactions to pain include rapid, shallow breathing; agitation; failure to groom; loss of appetite; and sleeping more than usual. Some will urinate or defecate inappropriately but don't move away from the "accident."