Your dog may live a comfortable life in your home, with access to a world of luxuries his wild ancestors couldn't dream of having. But he still has a very active set of survival instincts. Threats to his territory, unwanted attention from people and animals and even being separated from his pack can cause him stress. Fortunately, he's very good at communicating when he feels stressed, you just need to learn the non-verbal lingo.
A dog who is feeling stressed with typically give away his feelings quite obviously. However, if you don't speak "dog," these signs are quite easy to miss. Low tail carriage, hunching and shifting the weight between his left and right hind legs are all signs of stress that other dogs will quickly recognize. Your dog expects you to recognize these, too.
A dog can communicate a lot with his eyes. If he refuses to meet your gaze, or repeatedly looks away, he's being submissive. If he's being submissive, he's trying to say "Hey, I'm not a threat, please be kind to me." But if this submissiveness is ignored, your dog may begin to feel threatened. If he narrows his eyes, this is a reaction to feeling stressed. Lip licking, yawning, panting and pinning the ears back are all signs of stress.
Your dog has quite a vocabulary and there are many sounds that mean "OK, this is stressing me out, please stop." A whine or a whimper are typically the first audible signs of stress. If ignored, your dog may start to bark. If his whimpers and barks are ignored, he'll revert to a low, sustained growl. This must not be ignored, as it means your dog has run out of polite ways to tell you he's stressed and is now starting to feel anxious.
If your dog is subjected to sustained or regular stress, for example if you've just moved or if a member of family changes their routine or is absent, the residual stress may cause your dog's behavior to change. Excessive shedding, refusal to eat, restlessness and destructive behavior are all behavioral indicators of stress.