Some signs that a pet dog is nearing the end of his life is if he begins to lack the energy to move and seeks out quiet spaces inside the house. Other signs that indicate a pet dog is dying is if he starts to become sad and lashes out.
As a dog ages, his mobility starts to deteriorate alongside his stamina, causing him to be unable to move around as quickly as before. Once a pet dog finds moving around difficult, his time may be drawing near. In a home with multiple dogs, a dying dog may also become a target for bullying by other pets.