Dogs do not shed tears when they are sad or hurt, but they do vocalize in a way that is commonly referred to as crying. These vocalizations are also called whining and whimpering.
Humans are unique in their ability to shed tears because of their emotions. Vocalizations because of pain or distress are common, and they are used to communicate with other dogs or owners. Dogs may whine or cry when they want food or to go outside, when they are lonely, scared or excited, or when they are in physical pain. Dogs who appear to be shedding tears may have a medical problem and should be seen by a veterinarian.