• According to Texas A&M University, pets who become depressed will display behavior changes that indicate their mood. Pets are not always able to communicate feelings of sadness to their owners and it is up to the humans who take care of them to be on the lookout for these changes. With careful attention to your pet, you will be able to detect depression and begin finding ways to help him feel better.
  
  

Eating Habits

• Pets' eating habits change dramatically when they are depressed. Dogs and cats may eat to excess or they may eat very little and lose weight. Changes in eating habits are common in humans with depression as well. It is the change in habit and not necessarily the amount of food that is eaten that is the cause for alarm.
  
  

Sleeping

• Dogs and cats may begin to sleep more than usual when depressed. Their energy will seem low and they may spend more of their time sleeping than awake. Most cats and dogs sleep many hours during a day, but a depressed pet will also be lethargic when awake.
  
  

Loss of Interest in Activities

• When your cat or dog is not interested in a favorite toy or game, it might be a sign of depression. Toys and spending time playing games outside may seem to be the last things on your pet's mind. A game of tug of war is suddenly less interesting to your dog. The jingle balls that your cat once chased around the house for hours will sit in the corner unused if she is depressed.
  
  

Distance

• Your pet may keep his distance from the family while depressed. A dog or cat who is feeling depression symptoms may not spend time by his owner's side as he did in happier days.
  
  

Vocalizations

• Dogs and cats who are depressed over the loss of a playmate or family member may whine or cry more than usual. Cats tend to become very vocal when they are depressed over the loss of a loved one.
  
  

Refusing Water

• Not only does a depressed animal experience changes in appetite, she may even refuse water. This is a dangerous condition for a depressed animal and it is vital that you take your pet to the vet for evaluation when she is not drinking. Dehydration can occur rapidly in an animal who is not drinking fluids.
  
  

Restlessness

• Some dogs become restless when they are depressed. A pet may pace without finding a place to sit, or he may follow you around, though seemingly without any interest in spending time with you.
  
  

Shedding

• Anxiety and depression can lead to shedding. If you notice that your cat or dog is shedding more than usual, it may be a symptom of depression. Shedding may have medical causes and should be checked by a vet.
  
  

Lack of Grooming

• Depressed cats seem unable to groom themselves. A depressed cat may have matted fur or not spend time primping and grooming.