Instructions
Give your pet as much attention as you possibly can. Most pets are social animals and require attention. Pets that are used to animal companions will lose most of their social interaction when a companion pet dies. Play with your pet or even groom it if it enjoys that. Encourage snuggling with your pet. It is very important that your pet does not feel a great amount of loneliness.
Find a stuffed animal that is similar in size, color and shagginess to the departed pet. The animal will know that this is not its friend, but it will be comforting to it to have a similar object with which to cuddle.
Distract your pet when you see depressed behavior. Animals truly live in the moment. If you see your pet moping around the departed pet's favorite hiding spot, distract it with toys or loving play. The animal will soon forget its sadness temporarily.
Be patient. As with humans, depression in animals will eventually pass. It can take longer for some than others, and the pet may still exhibit depression-like behavior in the future. The key is to continue to provide a warm and loving atmosphere that is conducive to recovery.
How to Help a Pet Deal With the Loss of a Fellow Animal
Pets are important to many people. Most pet owners cherish their animals so much that they see their dogs or cats as members of the family. Therefore, it is painful to deal with the passing of a pet---but not only for the humans in the household. Families with multiple pets tend to notice depression or a change in behavior in the surviving animals once one pet has passed away. It is important for the humans in the house to be sensitive to this and to comfort their surviving pets as the pets comfort them.