Depression

• Dehydration will cause your cat to feel tired and listless. If you notice that she is sleeping a lot, has less-than-normal energy or is uninterested in her usual activities, she may be dehydrated.
  
  

Loss of Skin Elasticity

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  Perform the turgor test for skin elasticity: Gently grasp the skin at the base of your cat's neck and pull it up. If it springs back quickly, he is hydrated; if it is slow to retract, your cat is dehydrated.
  
  

Slow Capillary Refill

• Press your finger against your cat's gums. When you remove your finger, you will see a white spot where your finger was. In healthy cats, the pink will return in 1 to 2 seconds; any longer and your cat may be dehydrated.
  
  

Sunken Eyes

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  A lack of sufficient hydration will cause your cat's eyes to appear dull and sunken.
  
  

Dry Mouth

• Dehydration will cause your cat's gums to feel dry and sticky, rather than slick and moist, and his saliva will have a thick consistency.
  
  

Rapid Heartbeat

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  Dehydration could cause a increase in your cat's heart rate (normal rate is typically 110 to 140 beats per minute). To monitor your cat's heart rate, lay her on her right side, bend her left front elbow by pressing back against her paw and gently lay your hand on her chest behind her left elbow.